Place the yellow split peas in a fine-mesh sieve and rinse under cold water until the water runs clear. Optional: soak the peas in cold water for 30 minutes to 1 hour to reduce cooking time and improve texture, then drain.

Sweat aromatics

In a medium-large heavy pot, heat 2 tablespoons oil or ghee over medium heat. Add the finely chopped onion and a pinch of salt. Cook, stirring often, until the onion is soft and translucent, about 6–8 minutes. Add the minced garlic and grated ginger and cook another 1–2 minutes until fragrant, taking care not to burn the garlic.

Toast spices

Stir in the turmeric, ground cumin, and ground coriander and cook for 30–45 seconds to bloom the spices, stirring constantly so they don't stick or burn.

Add peas and liquid

Add the rinsed (and soaked/drained) yellow split peas to the pot and stir to coat with the spiced onion mixture. Pour in 6 cups of water and add the slit green chili if using. Bring the pot to a gentle boil over medium-high heat.

Simmer

Once boiling, reduce heat to low-medium to maintain a gentle simmer. Cover partially (lid tilted) and simmer for 30–40 minutes, stirring occasionally and skimming any foam that rises to the surface, until the peas are tender and breaking apart. If the mixture becomes too thick before the peas are fully tender, add hot water 1/2 cup at a time to reach desired consistency.

Season and mash

When the peas are tender, stir in 1.5 teaspoons kosher salt and 1/2 teaspoon freshly ground black pepper. Use the back of a spoon or a potato masher to gently mash some of the peas for a creamier texture, leaving some whole for body. Taste and adjust salt and pepper as needed.

Finish and garnish

Turn off the heat. Stir in chopped cilantro and squeeze lemon or lime to taste. Cover for 2 minutes to allow flavors to meld, then serve warm.

Optional tempering (tadka)

Prepare tempering

In a small skillet, heat 1 tablespoon oil or ghee over medium heat until shimmering. Add mustard seeds and cumin seeds. When they begin to pop (a few seconds), add the dried red chili and immediately sprinkle the asafoetida. Stir for 10–15 seconds until fragrant—be careful not to let the chili burn.

Finish with tempering

Pour the hot tempering evenly over the finished peas (ater kik) just before serving to add a bright, toasted flavor and aroma.