This caramelized onion and mushroom savory galette is a delightful rustic tart that combines a golden, flaky pastry with a hearty, deeply flavorful filling. Buttery pastry encases a melange of sweet caramelized onions and earthy mushrooms, enhanced with fresh thyme and a hint of balsamic vinegar for extra depth. The onions are cooked slowly until golden and sweet, then combined with sautéed mushrooms for a savory, almost meaty richness. A sprinkle of grated Gruyère cheese over the filling before folding in the pastry’s edges adds a creamy, nutty flavor and helps bind the filling. The free-form crust bakes to a golden crisp, contrasting beautifully with the soft, aromatic filling. Serve this delicious galette as a main course for a vegetarian dinner, a luxurious lunch, or slice it into wedges for an elegant appetizer at your next gathering. It’s sure to impress both vegetarians and meat-eaters alike, and can be enjoyed warm or at room temperature.