Preheat the oven to 400 degrees.

In a large skillet saute the onion in the olive oil and butter over medium heat for 15-20 minutes, stirring occasionally, until deep golden brown.

Add in the garlic, salt, and pepper and cook for 1-2 minutes. Remove from heat.

Meanwhile, bake the 24 puff pastry cups on 2 baking sheets for 15 minutes.

remove from oven and press down the centers.

Sprinkle 1 teaspoon of cheese in the cups, top with onions, and then sprinkle with more cheese.

Bake for an additional 5-7 minutes or until cheese has melted.

Serve warm.