Ingredients
1 sheet frozen puff pastry, thawed
2 tablespoons Dijon mustard
1 cup grated Gruyere cheese
1/4 finely grated Parmesan cheese
4 ounces very thinly sliced Black Forest ham
Instructions
Position the sheet of pastry on a lightly floured counter so that a short side is closest to you. Roll the pastry into a 10-by-14-inch rectangle. Trim the edges, if necessary, to make the rectangle neat,
Using the back of a spoon or an offset spatula, spread the mustard over the pastry. Distribute the Gruyere and Parmesan evenly over the surface. Arrange the ham in a single even layer, tearing or cutting pieces to fit. Lay a piece of parchment paper or waxed paper on top and gently compress the layers with the rolling pin. Peel off the paper without disturbing the ham.
Cut the rectangle in half widthwise to make two 10-by-7-inch bands. With your fingers, gently roll one short edge of one of the bands into the center and then roll the opposite edge in so the two rolls meet in the middle and resemble a double seroli. Press lightly so the rolls stick together (spread a few drops of water where the two rolls meet to help them stick, if necessary). Repeat with the second band. Wrap the rolls in aluminum foil and chili until they firm up, at least an hour in the refrigerator or 30 minutes in the freezer.
When you’re ready to bake, heat the oven to 425F and prepare baking sheets with parchment paper or silpat. With a very sharp knife, slice each roll into 12 pieces, arrange them on a sheet at least 1 inch apart, and bake until the pastry is nicely browned and flaky (break one apart to be sure it’s not still doughy in the center), and the cheese is melted but not burned, 10 to 12 minutes. Transfer the palmiers to a cooling rack.
Serve just slightly warm or within the hour, if possible.
