Onion Cake with Cheese

	Peel the onion and slice it into half rings. In a frying pan, heat 1 tablespoon of vegetable oil and sauté the onion, stirring constantly, for about 5 minutes until soft. Then remove from heat and let it cool.
	Prepare buttermilk. Pour vinegar into the milk and let it sit for half an hour.
	For the top layer, combine flour, butter, and water in a bowl. The dough should be very thick. Firmly press it into the bottom of the bowl, cover, and place it in the freezer for half an hour.
	Mix the pancake flour with regular flour, add half of the sautéed onion, half of the cheese, and chopped green onion. Beat the egg with buttermilk and 125 ml of vegetable oil, then pour it into the dough and gently mix.
	Preheat the oven to 200 °C. Grease a baking pan with vegetable oil and line it with parchment paper. Pour the onion dough into the pan.
	Grate the frozen dough and quickly mix it with the remaining fried onion and cheese. Spread it evenly in the pan. Place it in the oven and bake for 30 minutes.