Wash the toor dal, and add enough water to cover it, along with ¼ teaspoon turmeric powder and asafoetida. Pressure Cook the toor dal for five whistles or until fully done. Mash the cooked dal and keep it aside.
Soak marble-sized tamarind in 1 & ½ cups warm water and take extract. Keep it aside.
Crush or finely puree one tomato and keep it ready. Make juice with ½ cup of chopped pineapple along with a little water. Keep it ready.
Add a teaspoon of ghee to a pan. Add one finely chopped tomato and ¼ cup pineapple pieces. Saute well for a couple of minutes. Remove from pan and keep it aside.
Add tamarind extract, turmeric powder, salt, rasam powder, asafoetida, curry leaves, and pureed/crushed tomato to the same vessel.
Boil this well. Once it comes to a good boil, add pineapple puree. Mix well. Add the sautéed pineapple and tomato.
Add water and adjust the quantity according to your preference. Adjust salt if needed.
Boil once again. Add the mashed dal. Once the rasam froths on top, switch off and garnish with coriander leaves.
In a separate pan, add ghee. Add mustard seeds when the ghee is hot. When the mustard seeds start to sputter, add cumin seeds, asafoetida, and curry leaves and saute them for 30 seconds.
Add the seasoning to the hot rasam. The delicious pineapple rasam without garlic is ready to be served with rice.