Put the greens in boiling salted water (excluding the onions, parsley and spearmint) for 5 min. Then put them in a strainer and cut them finely.
Heat the oil and saute the finely chopped onions in it. Next, add the chopped greens.
Put everything in a pot and pour in a little warm water. Add the finely chopped parsley and spearmint and salt to taste.
Put it to bake in a moderate oven. Next, beat the ingredients for the topping together and pour them over the dish. Bake a bit more.