Carmelized Onion Tarts

These are fabulous!  I love carmelized onions. 

2 Tbs Olive oil
2 medium onions, sliced
2 red apples (gala or braeburn), cut into small pieces
Kosher salt and black pepper
2 sheets frozen puff pastry, thawed
1/2 cup creme fraiche or sour cream

Heat oven to 400.  Heat the oil in a large skillet over medium heat.  Add the onions and cook, stirring occasionally, until soft and golden brown.  Stir in the apples, 1/2 tsp salt, and 1/4 tsp pepper and cook until just tender, about 2 minutes. 

Place each sheet of pastry on a parchment lined baking sheet and prick all over with a fork.  Spread with the sour cream, leaving a 1/2 inch border.  Top with the onion mixture and bake until the pastry is crisp and browned, 30-35 minutes.  Cut into pieces before serving. 

Make ahead strategy:  The tarts can be assembled and frozen up to 1 month in advance.  Freeze them, unbaked, on parchment lined baking sheets until firm, then wrap in plastic.  To cook, bake from frozen at 400 for 40-50 minutes; keep warm at 250.  cut just before serving.  From Real Simple magazine.