Alsatian Onion Pie

6 ounces bacon, thinly sliced crosswise

4 cups thinly sliced yellow onion

Kosher salt and ground black pepper

8 ounces creme fraiche

1 large egg yolk

Pinch nutmeg

1 ½-pound ball purchased pizza dough, room temperature

3 ounces coarsely grated Gruyere cheese

In a large skillet over medium, cook the bacon, stirring, until it starts to brown, 5 to 8 minutes. Transfer the bacon to paper towels to drain and pour off all but 2 tablespoons of the fat from the skillet. Return the skillet to medium heat and add the onions. Cook, covered, stirring occasionally, until very soft, about 10 minutes. Remove the cover and cook, stirring occasionally, until golden, about another 30 minutes. Season with salt and pepper, then set aside.

Heat the oven to 500 degrees. Arrange one of the oven racks on the oven's bottom shelf.

In a small bowl, stir together the creme fraiche, egg yolk, nutmeg and a pinch each of salt and pepper.

Divide the dough into 3 even pieces. On a lightly oiled surface, roll out each piece into a 10-by-12-inch rectangle about ⅛-inch thick. Transfer each to a 15-by-17-inch sheet of kitchen parchment. The dough may shrink and lose its shape. If so, roll it again on the parchment.

One at a time, transfer each piece of parchment and dough to a baking sheet (unless your oven can fit 2 sheets on one shelf, you'll need to bake these one at a time). Spread a third of the creme fraiche mixture over the piece of dough on the baking sheet, then top with a third of the onions and bacon. Sprinkle with a third of the cheese, then bake on the oven's lower shelf for 10 minutes, or until the crust is crisp. Repeat with remaining dough and toppings. Serve right away.

Start to finish: 1 hour 15 minutes

Makes three, 10- to 12-inch pizzas

Nutrition information per half pizza: 640 calories; 310 calories from fat (48 percent of total calories); 35 g fat (16 g saturated; 0 g trans fats); 120 mg cholesterol; 1260 mg sodium; 60 g carbohydrate; 4 g fiber; 6 g sugar; 17 g protein.

Sara Moulton