Sometimes the appetizer can be the star of the show of your holiday feast, and these mushroom bites are proof! Take a bite out of the savory, puff pastry goodness, and see for yourself why this simple mushroom appetizer is the way to go.
- Preheat the oven to 400°F, and line a baking sheet with parchment paper.
- Heat 1 tablespoon each of oil and butter on medium heat in a large cast-iron skillet. Once heated, add the mushrooms, and cook for about 5 minutes. Remove, and set aside.
- Combine the remaining oil and butter in the same skillet, and add the onions. Cook until sautéed. Add the thyme and sugar, and cook for 25 minutes on medium-low heat, continually stirring.
- Add the balsamic vinegar to deglaze the pan, allowing the onions to soak in the excess juices—and turn off the heat.
- Put the onions in the mushroom mixture. Season with garlic powder, salt, and pepper, and stir. Wait until the mixture is at room temperature before proceeding.
- Add the Gouda, Gruyère, and bacon bits. Mix well. Using a knife or a pizza cutter, cut the puff pastry into 1½-inch squares, and place them on the lined baking sheet. Make sure the puff pastry squares are cold before continuing. If not, put them in the refrigerator for 10–15 minutes.
- Brush the lightly beaten egg onto the squares with a pastry brush. Add a tablespoon of the mushroom mixture to the center of each square. Bake for 20–25 minutes, rotating the pan halfway until the bites are crisp. Make sure they’re cool before serving.