Watermelon Rasam, or Darboosani Rasam, is a South Indian lentil soup made with fresh watermelon puree. It’s spicy and tangy, with just a hint of sweetness. Serve this easy rasam hot with rice for a light, comforting meal.
My Love For Rasam
If you follow my blog, you already know I love rasam. I have over 25 rasam recipes here, and many are fruit-based—pineapple rasam, cherry rasam, and lemon rasam. Watermelon rasam is the newest one to join the list. I know what you’re thinking. Won’t it be too sweet? That was my worry too. The trick is to bump up the tamarind and spices so they balance out the watermelon’s sweetness.
Recipe Inspiration
The story behind this recipe is what really pulled me in. This is one of Mountbatten Mani Iyer’s popular recipes. He runs a well-known catering service in Mylapore, Chennai. My friend JV showed me one of his cookery shows, and this rasam caught my eye right away. I had to try it. In his original recipe, he uses only the cooked toor dal water — not the dal itself — along with rasam powder and red chili powder. I made a few changes. I added the toor dal along with its water, and I used freshly ground pepper instead of red chili powder. He also uses katti perungayam (solid hing); I went with the powdered kind.
Ingredients Overview
- Toor dal — pressure-cooked with a little oil and turmeric, then mashed. It gives the rasam body. I always add a little oil when pressure-cooking, so the dal turns out soft and mushy.
- Tamarind paste — brings the tang and balances the watermelon’s sweetness. You can use my homemade tamarind paste.
- Rasam powder — the main spice base. Increase it if your watermelon is very sweet. You can use store-bought or my homemade rasam powder or kollu rasam powder too.
- Freshly ground pepper — my swap for red chili powder. Adds heat without the color.
- Watermelon puree — strained and filtered. This is the star.
- Cilantro and curry leaves — for freshness and aroma.
- Ghee — to fry the tadka and add richness.
- Mustard seeds, cumin seeds, and asafoetida — the classic rasam tempering.
Apart from these ingredients, you also need salt and water. Please check the recipe card for exact measurements.
Dietary Specs & Storage
This watermelon rasam is vegetarian. To make it vegan, swap the ghee in the tempering for gingelly (sesame) oil or any neutral oil. Everything else stays the same.
Store any leftover rasam in an airtight container in the fridge for 2 to 3 days. Reheat it gently on the stove or in the microwave, just until warm. Don’t let it come to a hard boil when you reheat.
Serving Recommendations
Serve watermelon rasam hot with steamed rice or millet and a side of poriyal. I highly recommend spicy poriyal like potato curry or raw banana fry.
How to Make Watermelon Rasam
- Wash and pressure-cook the toor dal with water, a little gingelly oil, and turmeric powder. Once it cools, mash it well and set aside.
- Puree the watermelon and extract about 1.5 cups of juice. Strain and filter it.
- In a heavy-bottomed pan or patram, add the tamarind paste, rasam powder, pepper powder, salt, and one cup of water. Mix well.
- Heat on medium flame and let it simmer.
- Once it starts to simmer, add the cilantro and curry leaves. Let it simmer again.
- Add the filtered watermelon puree and ½ cup more water. Simmer again.
- Add the cooked and mashed toor dal. Simmer.
- Once the froth forms, turn off the heat.
- In a separate tadka pan, heat the ghee. Add the cumin seeds, asafoetida, and mustard seeds.
- As they start to splutter, add the tempering to the rasam.
That’s it. Yummy watermelon rasam is ready. Serve hot with rice and poriyal.
Recipe Notes
- You can use toor dal water instead of mashed toor dal.
- Adjust the rasam powder based on how sweet your watermelon juice is. If needed, add ½ tsp of chili powder.
- Adjust the spices and salt to your taste.
- Traditionally, this rasam uses katti perungayam (solid hing) instead of the powdered kind. Use whichever you have.
Frequently Asked Questions
No. The extra tamarind and spices balance out the watermelon’s sweetness. Increase the rasam powder if your watermelon is very sweet.
Yes. You can use just the cooked toor dal water, like in the original recipe.
Increase the rasam powder, or add ½ tsp of red chili powder along with the pepper.
More Watermelon Recipes
Loved this recipe?
If you tried this watermelon rasam, please leave a comment and rate the recipe below. Got a question? Drop it in the comments, and I’ll get to it as soon as I can.
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📖 Recipe
Watermelon Rasam (Darboosani Rasam)
Ingredients
Measurement Details: 1 cup = 240ml; 1 tbsp = 15ml; 1 tsp = 5ml;
For the rasam
- ¼ cup toor dal
- ¼ tsp oil
- ⅛ tsp turmeric powder
- ½ cup water
- 1 tbsp tamarind paste
- 1.5 tbsp rasam powder
- ¾ tsp freshly ground pepper
- 2 tsp salt
- 1 cup water
- 2 tbsp cilantro
- 10 curry leaves
- 1.5 cups watermelon puree
- 1.5 cups water divided
To temper
- 2 tsp ghee
- ½ tsp mustard seeds
- 1 tsp cumin seeds
- a pinch of asafoetida
Instructions
- Wash and pressure-cook the toor dal with water, gingelly oil, and turmeric. Cool, mash, and set aside.
- Puree the watermelon and extract about 1.5 cups of juice. Strain and filter.
- In a heavy-bottomed pan, mix the tamarind paste, rasam powder, pepper, salt, and 1 cup water.
- Heat on medium flame and let it simmer. Add cilantro and curry leaves. Bring it to a gentle boil
- Add the watermelon puree and ½ cup more water. Simmer again.
- Add the mashed toor dal. Simmer. Once the froth forms, turn off the heat.
- In a tadka pan, heat ghee. Add cumin, asafoetida, and mustard seeds.
- Once they splutter, add the tempering to the rasam.
Video
Notes
- You can use toor dal water instead of mashed toor dal.
- Adjust the rasam powder based on how sweet your watermelon juice is. If needed, add ½ tsp of chili powder.
- Adjust the spices and salt to your taste.
- Traditionally, this rasam uses katti perungayam (solid hing) instead of the powdered kind. Use whichever you have.
Nutrition
I am not a nutritionist. The nutritional information is provided as a courtesy and is an estimate only. It varies depending upon the product types or brands.
Nice way to use watermelon in rasam. Loved your recipe.
Thanks Smruti.
Wow very nice idea of making rasam with water melon.
Thanks Sapana
Very interesting and innovative rasam with watermelon. Love the color of the rasam.
Me too. Thanks :-)
This rasam is new to me, very creative Vidhya. Looks very flavorful.
Thanks a lot Amara. :-)
This is an awesome innovative rasam. Looks so yum..
Thanks a lot Gayathri.
Watermelon Rasam surely is a new one..sounds very adventurous…:)
:-) Thanks a lot Valli.
I am not familiar with rasam but it looks like an interesting and tasty dish.
Welcome to my space. Rasam is like mild soup :-) Thanks a lot.
Interesting rasam!! Watermelon rasam is totally new to me. Looks spicy and flavorful!!
Thanks Usha.. Similar to pine apple rasam only. Please do try when you get a chance.
Hi Vidya…This watermelon recipe is new to me…Have made pine apple rasam…but this one have to give a try.
Hi.. how r u? Its pretty much similar to that.. Please do try pa.
Now you got my complete attention! I don’t think I have ever used the words watermelon and rasam in a single sentence. :))
That is one novel rasam.
ha ha thanks Suma. Thanks to my friend for introducing this recipe.
Your blog is beautiful! I’ll have to spend some time looking through your vast recipe list. @abetterjulie from http://www.persephoneknits.blogspot.com
Thanks a lot and welcome to my space.
Waiting for watermelon now, this rasam looks super comforting and flavourful.
Thanks Priya..
Yummy ….. sweet and spicy
Thanks a lot Bharani.
Wow! Very creative and awesome share.Thanks Vidya for a delicious Watermelon Rasam recipe..
Thanks a lot Deepa. :-)