Cook horsegram: Wash 1 cup ulavalu (horsegram). Pressure cook with 3 cups water for 8-10 whistles. Strain — save all the dark broth.
Make horsegram broth rice water: Grind half the cooked horsegram with broth to a smooth liquid. Combine all broth — you need about 3 cups liquid total.
Cook rice in horsegram broth: Wash 2 cups raw rice. Cook in the horsegram broth instead of water — use the same ratio as regular rice cooking. The broth infuses the rice.
Spread and cool rice: When cooked, spread on a plate and cool slightly.
Make tempering: Heat 3 tbsp sesame oil. Add 1 tsp mustard seeds. When they pop add 2 dried red chillies, 5 garlic cloves and curry leaves.
Add shallots: Add 8 sliced shallots and fry 8 minutes until golden.
Add spices: Add 1 tsp red chilli powder and salt. Fry 1 minute.
Add rice: Add the horsegram-cooked rice. Fold gently.
Mix evenly: Fold until rice is coated with the dark tempered oil. The rice will be a deep brown from the horsegram broth.
Serve: Adjust salt. Ulavacharu annam has an intensely earthy, nutritious flavour. Serve with papad and pickle.