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Crunchy and refreshing water chestnuts pieces are wrapped in soft and chewy tapioca dough, resembling red ruby gems. The dessert is served in rich and creamy coconut milk infused with pandan flavor.
Tub tim grob or tub tim krob is one of Thai’s popular dessert. It’s such a refreshing dessert to have especially when the weather is hot and humid. Some said it is named as Thai ruby dessert because of its resemblance to rubies or pomegranate (Tub Tim). Some said they look like pomegranate seeds, which they are too. Grob or krob means crunchy in Thai.
Tub tim grob looks pretty fancy but they are actually pretty simple to make. In a nutshell, diced water chestnuts are coated with tapioca flour and then boiled and served with simply syrup and coconut milk. Perfectly vegan and dairy-free here 🙂
How to make tub tim grob
1. I used canned water chestnuts that have been peeled. Dice them into 1/2-inch pieces. Get two large bowls, one for red and one for blue rubies
2. If using natural coloring, mix the red yeast rice powder with hot water and stir to dissolve. Strain the mixture and then add 100 grams of the water chestnuts and let them soak for at least 15 minutes. Soak the blue pea flowers in hot water for 15 minutes. Discard the flowers and collect the blue liquid. Soak the rest of the water chestnuts for at least 15 minutes.
If using food coloring, put 2 Tbsp of water and 1-2 drops of red food coloring in the bowl. Add the water chestnuts pieces into the red and another 100 gr of water chestnut into the blue food coloring
3. Put ingredients in a saucepan and let it simmer until sugar dissolves. Remove from the heat and set aside
4. Put all ingredients in a saucepan and let it simmer gently for about 5 minutes. Don’t let it boil over. Remove from the heat and keep it chilled until ready to serve
5. Bring a large pot of water to a boil. Drain off the red and blue liquid
6. Sprinkle the first 1/3 cup of tapioca flour on the red rubies and another 1/3 cup of tapioca flour on the blue ones. Toss them to coat with flour
7. Then add a second 1/3 cup of tapioca flour on the red rubies and another 1/3 cup of tapioca flour on the blue ones. Toss them lightly to coat
8. Use a sieve to shake off excess flour. The rubies should be fully coated and white in color
9. Put the rubies in the boiling water and stir to prevent the rubies from sticking to each other at the beginning. Let the water comes back to a boil and when the rubies float to the top, let them cook for another 2 minutes or so
10. Remove from the boiling water using a sieve
11. Immediately transfer to a bowl of ice-cold water to stop the cooking process
12. Put about 2 Tbsp of syrup. Portion out the red and blue rubbies and then ladle the chilled coconut milk sauce over. Add more ice cubes if you like and serve immediately
Tips
1. Use canned water chestnuts that have been peeled to save you some work
2. Coat the tapioca flour in batches, don’t dump it all in at once
3. Make sure the water has come to a rolling boil before you boil the rubies
4. Tub tim grob is best consumed on the same day they were made as the tapioca portion of tub tim grob will harden if you refrigerate them
Did you make this tub tim grob recipe?
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Tub Tim Grob (Thai Red Ruby Dessert)
Ingredients
Red rubies:
- 100 gr canned water chestnuts
- 80 gr tapioca starch or more as needed
- 1 Tbsp red yeast rice powder or use few drops of red food coloring + 2 Tbsp water
- 100 ml hot water (to mix with red yeast rice powder) omit if you use red food coloring
- ice water
Blue rubies:
- 100 gr canned water chestnuts
- 2 Tbsp water
- 80 gr tapioca starch or more as needed
- 30 pieces dried blue pea flowers or use few drops of blue food coloring + 2 Tbsp water
- 100 ml hot water (to soak the flowers) omit if using blue food coloring
- ice water
Coconut milk sauce:
- 250 ml coconut milk
- 100 gr sugar
- 100 ml water
- ⅛ tsp Salt
- 2 pandan leaves knotted
Instructions
Prepare red and blue rubies:
- I used canned water chestnuts that have been peeled. Dice them into 1/2-inch pieces. Get two large bowls, one for red and one for blue rubies
- If using natural coloring, mix the red yeast rice powder with hot water and stir to dissolve. Strain the mixture and then add 100 grams of the water chestnuts and let them soak for at least 15 minutes
- Soak the blue pea flowers in hot water for 15 minutes. Discard the flowers and collect the blue liquid. Soak the rest of the water chestnuts for at least 15 minutes
- If using food coloring, put 2 Tbsp of water and 1-2 drops of red food coloring in the bowl. Add the water chestnuts pieces into the red and another 100 gr of water chestnut into the blue food coloring. Let them soak while you prepare other things
Prepare coconut milk sauce:
- Put all ingredients in a saucepan and let it simmer gently for about 5 minutes. Don't let it boil over. Remove from the heat and keep it chilled in the fridge until ready to serve
Coat chestnuts with tapioca flour:
- Bring a large pot of water to a boil. Drain off the red and blue liquid. Sprinkle the first 1/3 cup of tapioca flour on the red rubies and another 1/3 cup of tapioca flour on the blue ones. Toss them to coat with flour
- Then add a second 1/3 cup of tapioca flour on the red rubies and another 1/3 cup of tapioca flour on the blue ones. Toss them lightly to coat. Use a sieve to shake off excess flour. The rubies should be fully coated and white in color
Boil the rubies:
- Put the rubies in the boiling water and stir to prevent the rubies from sticking to each other at the beginning. Let the water comes back to a boil and when the rubies float to the top, let them cook for another 2 minutes or so
Check for doneness:
- The cooked rubies should be transparent. If you see lots of white specks, the rubies are not cooked through yet, let them cook for few more minutes
Soak in ice water:
- Remove from the boiling water using a sieve and immediately transfer to a bowl of ice-cold water to stop the cooking process
To serve:
- Portion out the red and blue rubbies and then ladle the chilled coconut milk sauce over. Add more ice cubes if you like and serve immediately
2 comments
Can it use corn flour instead of tapioca? Thank you!
Hello, unfortunately, No, it won’t give the chewy texture if you use corn starch/flour.