Red Rubies Dessert (Tub Tim Grob)

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Red rubies dessert, also known as Tub Tim Grob, is a refreshing Thai dessert filled with red rubies, jackfruit, coconut sauce, syrup, and crushed ice. You’re in for a real treat!

side view of layered red ruby dessert in a clear bowl.

What is Red Rubies Dessert?

Red rubies dessert, also known as “Tub Tim Grob” or “Tab Tim Krob,” is a popular Thai dessert known for its vibrant colors and unique textures. The dessert is often served in coconut milk and consists of several key components like red rubies, coconut milk sauce, syrup, and crushed ice.

The “rubies” in the dessert are small, translucent cubes made from water chestnut coated with tapioca flour or arrowroot powder. These red or pink cubes resemble rubies, giving the dessert its name. The water chestnut rubies have a crunchy texture.

The water chestnut rubies are typically served in a sweetened coconut milk base. The coconut milk is often flavored with pandan leaves to add a subtle aromatic note.

The dessert is drizzled with a syrup made from rose water or other flavored syrups, adding additional sweetness and fragrance.

Crushed ice is optional, but it provides a refreshing and cooling element to the dessert, especially in warm weather.

Red rubies dessert is known for its delightful combination of textures — the crunchy water chestnut rubies contrasting with the creamy coconut milk. The dessert is not only visually appealing but also offers a unique blend of flavors. It is enjoyed as a refreshing treat in Thai cuisine, and you can see it served anywhere from street food stalls to upscale restaurants.

tum tim grob in a glass bowl.

Why You’ll Love This Recipe

You’ll love it for its vibrant colors and contrasting textures. The dessert’s striking appearance, featuring vivid red rubies suspended in creamy coconut milk, makes it visually appealing. The combination of textures is an interplay of crispy and creamy textures.

This recipe allows for customization, such as adding crushed ice for a refreshing element or other fruits like lychee and longan. This flexibility allows you to tailor the dessert to your personal preference.

It’s a refreshing summer treat: Served cold, this red rubies dessert is a refreshing option during warm weather. But you can really have it anytime!

Gather These Kitchen Tools

  • Measuring Cups and Spoons
  • Small Pot
  • Fine Mesh Strainer
  • Slotted Spoon

Ingredients Needed

For the Red Rubies:

Red rubies or faux pomegranate ingredients: whole water chestnuts, tapioca starch, and red food dye.

Please scroll ⬇️ to the recipe card to see the full ingredient amounts and instructions.

The “red rubies” or sương sa hạt lựu are made of water chestnuts, red food coloring, and tapioca starch. They’re supposed to imitate pomegranate seeds. Use whole water chestnuts since they retain less water from the canned preservatives. If you can’t find water chestnuts, you can substitute it with apple, pear, or jicama.

For the Coconut Sauce and Syrup:

Labeled ingredients needed for coconut sauce and sugar water.

Please scroll ⬇️ to the recipe card to see the full ingredient amounts and instructions.

For the coconut milk sauce, you’ll need coconut milk, salt, and pandan leaves. No need to add sugar since the sauce is supposed to balance out the syrup.

The syrup consists of sugar, water, and pandan leaves. Fold the pandan leaves over a few times and tie them into a knot so that they’ll fit in the pot. If you can’t find pandan leaves, you can substitute them with pandan extract.

How to Make Red Rubies

Cutting water chestnuts into small cubes on a cutting board.
Adding red food coloring to chopped water chestnuts.

Step 1: Completely drain the water chestnuts from the can. Cut the water chestnuts into small cubes, about ¼ inch. Place it into a medium bowl and stir in 3 drops of red food dye. Toss until all the pieces are evenly coated.

Adding tapioca starch into a bowl with colored water chestnuts.
Adding the tapioca starch coated water chestnuts into boiling water.

Step 2: Add tapioca starch and stir to coat evenly. Remove any excess tapioca starch by using a colander to sift.

Step 3: In a small pot, bring 2-3 inches of water to a boil over medium-high heat. Add the chestnuts in and give it a quick swirl to avoid them clumping together. Cook for 2-3 minutes or until it floats to the top.

Using a slotted spoon to scoop red rubies into an ice water bath.

Step 4: Once it is done cooking, use a slotted spoon to scoop it out and place it directly into a bowl of ice water. Give it a good stir. Let it cool in the ice bath for at least 10 minutes to prevent sticking.

How to Make Coconut Sauce

coconut sauce in pot.

Step 5: In a small pot on medium low heat, bring the coconut milk, pandan leaf, and salt to a boil. Lower the heat if needed and let it slowly simmer for 4-5 minutes until the salt is dissolved. Place the coconut mixture in a bowl and put it in the fridge to let it cool.

How to Make Sugar Water

Knotted pandan leaves in pot of boiling water.

Step 6: In a small pot, add water, sugar, and pandan leaves. Turn the heat to medium and bring the water to a boil. Let it simmer for 4-5 minutes, stirring occasionally, until the sugar is dissolved and the pandan flavor is extracted into the water. Discard the pandan leaves. Place the sugar water into a bowl and place it in the fridge to let it cool.

How Assemble and Serve

Prepped ingredients needed to assemble red rubies dessert.

For serving, gently separate the water chestnut rubies as needed. Ensure both the coconut milk and sugar syrup are thoroughly chilled, as this dessert is intended to be served cold. The red rubies can be left at room temperature for a few hours, since the tapioca may harden if it is refrigerated.

Assemble the dessert in elegant serving bowls or glasses, layering a generous portion of the water chestnut rubies, sliced jackfruit, and crushed ice. Gently pour the chilled, sweetened coconut milk over the rubies, and drizzle a bit of sweetened syrup over the dessert. Serve immediately, to enjoy it at its peak with the crunchy rubies.

tub tim grob in a bowl with red rubies and jackfruit slices.

Helpful Tips

  • Completely drain and dry the water chestnuts with a paper towel. This will ensure that the tapioca starch sticks to the water chestnuts.
  • Use a colander to sift the excess tapioca starch off.
  • When adding it to boiling water, do not overcrowd it. Stir as you pour in the red rubies to prevent them from sticking together.
  • Have the ice water bath ready before boiling. It only needs to cook for 2-3 minutes, and you will need to quickly submerge the cooked red rubies into an ice water bath to cool it down.
  • Let it cool in the ice water bath for at least 10 minutes to prevent them from sticking together. Don’t leave it in the water for more than 30 minutes.
  • Avoid putting the rubies in the fridge, as it’ll harden. It’s best eaten on the same day.
side view of layered red ruby dessert in a clear bowl.

Storage Tips

Refrigerate: If you need to store the dessert for a short period, you can refrigerate it. Place the red rubies in an airtight container, and store the sweetened coconut milk separately. Keep all components in the refrigerator for up to 1-2 days.

Separation of Components: It’s advisable to store the water chestnut rubies, sweetened coconut milk, sugar water, and crushed ice separately to prevent the rubies from becoming overly soft. This ensures that the dessert maintains its intended texture when ready to serve.

Freezing (if necessary): While it’s generally not recommended to freeze red rubies dessert due to its texture, you can freeze the water chestnut rubies alone for up to a month. However, keep in mind that freezing may alter their texture, making them softer upon thawing.

Avoid Tapioca Hardening: This dessert contains tapioca-coated rubies, be cautious about extended refrigeration, as the tapioca may harden over time. It’s best to consume the dessert within a day or two for the optimal experience.

Bring to Room Temperature: Before serving refrigerated red rubies dessert, allow it to come to room temperature for a short period. This helps restore the desired textures and flavors.

More Recipes Like This

Did you know this dessert closely resembles the Vietnamese dessert – Che Thai? Che Thai has a creamy base with colorful fruits, chewy jelly, and even red rubies!

If you love this recipe, check these out: banana tapioca pudding, che chuoi, Vietnamese three layer dessert, che ba mau, or pandan jelly dessert, cendol.

RECIPE

Red rubies dessert (tub tim grob) in glass bowl. Layers of red rubies, jackfruit, coconut milk sauce, sugar water, and crushed ice.

Red Rubies Dessert (Tub Tim Grob)

Quynh Nguyen
Step by step of how to make Tub Tim Grob – a refreshing Thai dessert filled with red rubies, jackfruit, coconut sauce, syrup, and crushed ice. You're in for a real treat!
5 from 4 votes
Prep Time 6 minutes
Cook Time 15 minutes
Total Time 21 minutes
Course Dessert
Cuisine Thai
Servings 6 servings
Calories 234 kcal

Ingredients
  

For the Red Rubies

  • 1 (8 oz) can whole water chestnuts
  • 3 drops red food coloring
  • cup tapioca starch

For the Coconut Milk Sauce

  • 1 can coconut milk
  • 1 pandan leaf folded into thirds and tied into a knot
  • ½ teaspoon salt

For the Sugar Syrup

  • 1 cup water
  • ½ cup sugar
  • 1 pandan leaf folded into thirds and tied into a knot

For Serving

  • crushed ice
  • ripe jackfruit, cut into slices

Instructions
 

Make the Red Rubies

  • Completely drain the water chestnuts from the can. Cut the water chestnuts into small cubes, about ¼ inch. Place it into a medium bowl and stir in 3 drops of red food dye. Toss until all the pieces are evenly coated.
  • Add tapioca starch and stir to coat evenly. Remove any excess tapioca starch by using a fine mesh colander to sift.
  • In a small pot, bring 2-3 inches of water to a boil over medium-high heat. Add the chestnuts in and give it a quick swirl to avoid them clumping together. Cook for 2-3 minutes or until it floats to the top.
  • Once it is done cooking, use a slotted spoon to scoop it out and place it directly into a bowl of ice water. Give it a good stir. Let it cool in the ice bath for at least 10 minutes to prevent sticking.

Make the Coconut Sauce

  • In a small pot on medium low heat, bring the coconut milk, pandan leaf, and salt to a boil. Lower the heat if needed and let it slowly simmer for 4-5 minutes until the salt is dissolved. Place the coconut mixture in a bowl and put it in the fridge to let it cool.

Make the Sugar Syrup

  • In a small pot, add water, sugar, and pandan leaves. Turn the heat to medium and bring the water to a boil. Let it simmer for 4-5 minutes, stirring occasionally, until the sugar is dissolved and the pandan flavor is extracted into the water.
  • Discard the pandan leaves. Place the sugar water into a bowl and place it in the fridge to let it cool.

Assemble and Serve

  • Once the ingredients are cooled, gently separate the red rubies, if needed. Assemble the dessert in elegant serving bowls or glasses, layering a generous portion of the water chestnut rubies, sliced jackfruit, and a layer of crushed ice. Gently pour the chilled, sweetened coconut milk over the rubies and drizzle a bit of sweetened syrup over the dessert.
  • Serve immediately and enjoy!

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