Pour water, oil into a saucepan, pour salt and sugar, bring to a boil. Pour vinegar, add peppercorns and bay leaf. Pour mushrooms, cover, let the brine boil. Cook mushrooms on low heat for 40 minutes, no less. When the mushrooms are cooked, turn off the heat, let cool. Pour into a glass dish and let it brew for a day. Ready-made mushrooms can be served.