1. Preheat the oven to 400°F, and line a baking sheet

with parchment paper.

2. Heat 1 tablespoon each of oil and butler on medium

heat in a large cast-tron skillet Once heated, add the

mushrooms, and cook for about 5 minutes, Remove,

and set aside.

3. Combine the remaining oil and butter In the same skillet,

and add the onions. Cook until soutéed. 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.

4. 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.

5. 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.