Peel the onion, finely chop and brown in 1 tbsp. l. oil heated in a saucepan. Add peas, a pinch of salt, mix. Cover with a lid and simmer over low heat for 10 minutes. Pepper and chill. Beat eggs with milk and a pinch of salt. Add the cooled peas with onions to the egg mixture, mix well. With the remaining oil, grease the inside of 8 small cake molds with a diameter of 5-6 cm and put the egg mixture with peas in them. Preheat the oven to 180ºС. Place the molds on a baking sheet and bake for 10 minutes, until the egg mixture is fluffy and the muffins are golden brown. Remove the finished cupcakes from the oven, cool and serve.