For the green chutney: Place the roasted peanuts (or dal) in a food processor with 1/3 cup of water. Puree until smooth. Add the entire bunch of cilantro including stems, serrano chile, garlic, lime juice, and sugar. Puree again until smooth. Add additional water if the sauce is too thick for dipping, then season with salt to taste.For the potato cakes: Peel cooked potatoes and place the flesh in a large bowl. Discard the peels. Use a potato masher to smash the potatoes into a fine ground.Add eggs, scallions, all spices, and salt. Mix by hand until well combined.Heat a large skillet to medium heat. Place a dollop of coconut oil in the skillet. Once melted, use a 1 ½ tablespoon scoop to measure out evenly-packed portions of the potato mixture. Place them in the skillet 2 inches apart and press them into ½-inch patties with the back of a spatula.Cook for 2–3 minutes per side, until golden, them move the patties to a plate and repeat with remaining potato mixture.Serve warm with green chutney for dipping. Garnish with cilantro and red onion if desired.