Put the potato in a medium pot and cover it with 1 inch of water. Cook until the potato is soft, then drain the water using a colander. Mash the potato with a fork and set it aside.
Put the pot back on medium heat and melt the butter. Add the onion and ½ teaspoon of salt, cooking for about 6 minutes until the onion is soft and just starting to brown.
Add the jalapeño and ginger, cooking for one more minute. Then, add the spices and stir for about 30 seconds until they smell fragrant.
Mix in the mashed potato, remaining salt, frozen peas, and cilantro. Stir everything together until well combined, then put it in the fridge to cool.
Notes
1 pound of potatoes is roughly equal to 1 large russet potato or 2 medium yellow potatoes.Taste the seasoning before completing the filling to ensure it isn’t bland.Adjust the number of jalapeños to control the heat level.