This are super easy and delicious!  You can make your own puff pastry which I did for those in the picture but sometimes cutting corners is okay!  I feel like for these using frozen puff pastry is perfect and great for a quick appetizer.

• 1 tablespoon extra virgin olive oil
• 1 tablespoon salted butter
• 2 sweet onions, sliced
• 2 teaspoons Worcestire sauce
• 2 teaspoons brown sugar
• 1 tablespoon fresh thyme
• 1/2 cup beef broth
• 3 tablespoons heavy cream
• 1 package of puff pastry (or homemade)
• 12 tablespoons gruyere cheese, 
• shredded
• fresh chives 

Preheat oven to 400F. Grease a 12-cup muffin tin with nonstick cooking spray.

Saute the onions in the olive oil and butter over medium heat. This should take around 30 minutes. Stir in sugar, salt, pepper and thyme.

Add the beef broth and worcesterhsire sauce and bring the mixture to a simmer. Simmer until the liquid has reduced almost entirely. Stir in the heavy cream.

Roll out the puff-pastry dough a little to flatten it. Cut the dough into 3 inch circles and then press into the cups of the prepared muffin tin.

Place 2 tablespoons of the onion filling into each cup and then top with 1 tablespoon grated Gruyere. Top with fresh chives.

You can also top these with different cheeses such as Fontina, Comte or Jarlsburg.  

Bake for 15 minutes.