This irresistible flatbread is classic French Onion Soup in pizza form. For a vegetarian version, simply use rich mushroom broth instead of beef.
Ingredients
- 12 oz ball of uncooked pizza dough
- 1 lb (~ 2 medium large) yellow onions
- 1 Tbsp butter, vegan butter, or mild olive oil
- 1-2 sprigs fresh thyme, or scant ¼ tsp dried thyme leaves
- ½ cup beef (or mushroom) stock
- 2 tsp minced garlic (~ 2 cloves)
- 1 tsp dijon mustard
- 1 tsp crème fraîche or full-fat sour cream
- 4 oz aged gruyère cheese
- (optional) pinch of minced parsley to garnish
Directions
Line a pizza peel or rimless cookie sheet with a piece of parchment paper. Put the pizza dough on the parchment, cover with plastic wrap and let it come to room temperature.
Peel and slice the onions into ¼” thick slices. In a wide, straight-sided skillet, melt the butter/oil over medium heat and stir in the sliced onions, thyme, and a small pinch of salt and pepper. Crumple a second piece of parchment paper into a ball, then flatten it out again, trim off the corners, and use to cover the onions as they cook. Stir the onions every few minutes to prevent sticking and burning. Whenever they start to dry out, add a splash of stock to rehydrate and help them cook through. When you run out of stock, continue adding splashes of water as needed.
When the onions are completely soft, stir in the minced garlic, remove the parchment cover, lower the heat and continue cooking until all excess moisture has evaporated. Remove the pan from the heat. (Onions can be prepared to this point 1-2 days ahead.)
Preheat the oven to 450 F. Roll out the pizza dough to a 9- to 10-inch diameter on the parchment paper. Use scissors to trim the parchment around the flatbread, so the paper extends just a few inches beyond the edge of the dough.
Coarsely grate the gruyère. Remove any thyme stems from the caramelized onions and discard. Stir the dijon mustard and crème fraîche into the pan of onions, then stir in about one-third of the grated gruyère. Spread the onion mixture evenly over the pizza dough, leaving a half-inch edge around the outside. Cover the onions with the remaining gruyère and some freshly ground pepper. Remove stray pieces of cheese and onions from the parchment paper to minimize burning. Bake the flatbread (on its parchment) directly on the oven rack for 13-17 minutes, or until the crust and topping are nicely browned but not burnt.
Carefully remove the flatbread from the oven, peel off the parchment underneath, and set it on a cooling rack a few minutes before transferring to a cutting board and slicing into wedges. Garnish with a bit of minced parsley if desired.