onion tarte

Onion tarte doesn't sound too appealing, huh?  Even if you call it a tarte instead of a pizza, like it really is?  :)
What about if it looks like this??

This tarte is great.  The onions get super sweet and caramel-y and the mustard really brightens things up.  It's great to serve with soup (like we did) or as appetizers for a dinner party.  It's homey but fancy and just plain delicious. 
Might sound strange to have a whole pizza with just onions, but trust me, if you call it a tarte, it transforms :)

Onion Tarte

Adapted from Gourmet 

Serves 8, as appetizers

One recipe pizza dough, or store-bought
Olive oil
3 pounds yellow onions, halved and thinly sliced
1 teaspoon salt
1/2 teaspoon pepper
2 tablespoons Dijon mustard
1 cup Parmigiano Reggiano, shaved

Roll out the pizza dough into a big rectangle, 15"x12".  Lay on a foil or parchment-lined baking sheet and set aside.
Meanwhile, heat some olive oil in a large heavy Dutch oven over medium low heat.  Add sliced onions and the salt and pepper.  Cover with a lid or a piece of parchment paper and cook until onions are very soft and dark golden brown, about an hour and a half. 
Preheat oven to 375*.
Brush the pizza dough with the mustard and spread onion mixture evenly over the surface.  Sprinkle with the cheese and bake for 30-35 minutes, or until tarte is golden brown.  Cut into diamonds (it's pretty!) and serve!