Ham and Cheese Pastry Pockets Ingredients 1 (14- to 17.5-ounce) package frozen puff pastry (preferably Pepperidge Farm), thawed but still cold 2 tablespoons unsalted butter 1/4 cup all-purpose flour, plus more for rolling 1 1/4 cups whole or 2% milk 1 1/2 cups shredded Swiss, sharp white cheddar cheese, or a combination, divided (about 6 ounces) 1 1/2 cups small-dice cooked ham (about 6 ounces) 1 ounce fresh baby spinach leaves, coarsely chopped (about 1 cup) 1 teaspoon white wine vinegar 1/2 teaspoon dry mustard powder 1/4 teaspoon kosher salt 1 pinch freshly ground black pepper 1 large egg 1 tablespoon water Instructions Step 1 Arrange two racks in the oven to divide the oven into thirds, then heat the oven to 400°F. Line 2 baking sheets with parchment paper. Step 2 Melt 2 tablespoons unsalted butter in a medium saucepan over medium heat. Add 1/4 cup all-purpose flour and cook, whisking constantly, until the mixture resembles wet sand and no longer has the aroma of raw flour, 2 to 3 minutes (do not let it brown). Whisk in 1 1/4 cups whole milk until smooth. Bring to a simmer. Cook, whisking constantly, until the mixture is thickened enough to coat the back of a spoon, 1 1/2 to 2 minutes. Step 3 Whisk in 1 cup of the shredded Swiss cheese until melted. Remove the saucepan from the heat. Stir in 1 1/2 cups small-diced cooked ham, 1 cup chopped fresh baby spinach leaves, 1 teaspoon white wine vinegar, 1/2 teaspoon dry mustard powder, 1/4 teaspoon kosher salt, and 1 pinch black pepper. Step 4 If using puff pastry that comes in only 1 sheet, cut in half crosswise into 2 sheets first. Place 1 of the sheets on a cutting board. Roll out if needed into a 12-inch square. Cut into 9 (4-inch) squares. Transfer the squares to a baking sheet, spacing them evenly apart. Repeat cutting the second puff pastry and transferring to the second baking sheet. Dock the center of each square a few times with a fork. Step 5 Spoon 2 tablespoons of the ham mixture onto the center of each square. Fold the corners of the pastry up over the filling until they meet in the center. Beat 1 large egg with 1 tablespoon water together in a small bowl. Brush onto the pastry. Sprinkle with the remaining 1/2 cup shredded Swiss cheese. Step 6 Bake for 12 minutes. Rotate the baking sheets between racks and from front to back. Bake until the pastries are puffed and golden-brown, 12 to 14 minutes more. Let cool for 3 minutes before serving. Recipe Notes Puff Pastry: Look for puff pastry sheets in the freezer section. For best results, thaw in the refrigerator for at least 4 hours and up to 1 day before using. Storage: Leftovers can be refrigerated in an airtight container for up to 4 days. Rewarm in a 325°F oven until warmed through. Yield: 10 pastry pockets Prep Time: 5 minutes Cook Time: 30 minutes Total Time: 35 minutes