I googled & found this recipe on veg recipes. I made it like the recipe with some differences.
Ingredients : 1/4 cup tur dal, 1 packet pineapple slices ( cost Rs 10 ), 1-2 tsps rasam powder, 1 /2 tsp jeera, 1/4 heaped tsp black peppercorns, 1 large tomato chopped fine & pureed in mixer, 1tbsp ghee, 1/2 tsp mustard seeds, 1 red dry chilly, 1/4 tsp powdered hing, 1/4 tsp haldi, few kadipattas,salt to taste.
Method : Pressure cook tur dal with haldi & hing for two whistles & then on slow gas for up to 10 minutes. Put off gas.after the cooker has cooled off, mash the tur dal Keep aside.
Take half of the sliced pineapple pieces & puree in mixer. Keep aside.
Remaining slices of pineapple are chopped finely & kept aside.
In small grinder jar, grind the jeera & black peppercorns to a coarse powder. Keep aside.
In a vessel, add 1 tbsp ghee.Put on gas. As the oil heats up, add mustard seeds. After they crackle, break the red chilly into some pieces & add to the oil.Add the curry leaves now. Now add the pureed tomatoes to the vessel.Allow it to come to a boil.Add salt. Mix nicely. Add the coarsely ground jeera black peppercorn mixture to the vessel,.Mix nicely with the tomato puree .Let it cook for a minute or two.Add the pineapple puree now. Mix nicely. Add the mashed tur dal now .Mix nicely.Add rasam powder now. Add water depending on the kind of rasam that is needed...thin or thick.
Add the finely chopped pineapple pieces to the rasam now. Bring it to boil.Put off gas.
Serve pinapple rasam with rice .
I forgot to add jeera pepper powder to the ghee in vagar & hence, added after tomato puree had boiled. And I added pineapple pieces at the end. In the recipe, these are added after tur dal is added.Maybe , if you follow recipe, it would turn out more flavorful.I have used smaller quantities of jeera & peppercorns as I am not used to very pungent flavours.