Young Onion Tart with Cantal, Applewood-Smoked Bacon, and Herb Salad

Preheat the oven to 400°F.

Defrost the puff pastry slightly and unroll it onto a parchment-lined baking sheet. Use a paring knife to score a 1/4-inch border around the edge of the pastry. Make an egg wash by whisking one egg yolk with 1/2 teaspoon water, and brush the egg wash along the border. (You will not need all of the egg wash.) Return the puff pastry to the freezer until you’re ready to use it.

Slice the bacon into 3/8-inch-thick slices. Stack the slices in two piles, then cut the bacon crosswise into 3/8-inch even-sided rectangles or lardons.