Tarte Flambee

Put a pizza stone on a rack in the upper third of the oven. Preheat the oven to 550ºF and let the stone heat at that temperature for 10 minutes.

Stir the creme fraiche, nutmeg and egg yolk together in a small bowl with a large pinch of salt and a few grinds of pepper.

Put the bacon in a large skillet over medium heat and cook, stirring occasionally, until some of the fat has rendered and the bacon is just starting to crisp, about 7 minutes. Carefully drain off most of the fat, then add the leeks. Cook, stirring, until the leeks just start to wilt, about 3 minutes.

Divide the pizza dough in half and lay on a lightly floured work surface. Roll and stretch one piece of dough into a very thin, organic shape (1/8 to 1/4 inch thick). Put the dough on a piece of parchment paper. Spread half of the creme fraiche mixture evenly on top, leaving a 1-inch border all around. Top with half of the bacon and leeks, then top with half the Gruyere. Put the pizza and parchment on a flat baking sheet or pizza peel and transfer to the pizza stone; bake until the crust is golden brown and charred in spots, 8 to 10 minutes. Repeat with the remaining dough and toppings. Cut into pieces and serve warm or at room temperature.