Caramelized Onion & Gruyère Galette

Piles of Spanish onions are slowly caramelized in butter and thyme, then layered in all-butter pastry with aged white cheddar, peppery bechemel, Parmesan and Gruyère. Heaven! 

Ingredients: Spanish onions, butter, AP wheat flour, cheddar, Gruyère, parmesan, milk, cream, olive oil, thyme, black pepper, nutmeg, sea salt, egg.