Soft boil the yam and raw banana, then mash them and set aside.

Grind grated coconut and cumin seeds into a fine paste by adding water gradually.

Heat oil in a pan and add the mashed vegetables.

Add salt, turmeric powder, peppercorns, chili powder, and the ground coconut paste.

Simmer for 3-4 minutes, adjusting water levels as needed, then switch off the heat.

In a separate small pan, heat coconut oil and temper with cumin seeds, mustard seeds, and dry red chilies.

When the mustard seeds splutter, add grated coconut.

Add curry leaves, turmeric powder, and chili powder; fry until the coconut turns crunchy and light brown.

Switch off the heat and pour this tempering over the erissery.

Serve Chena Kaya Erissery hot.