Preparation

1. To make the dough: Using an electric mixer at medium-high speed, cream the butter, gradually adding the sugar. Beat in the egg until evenly mixed, then blend in the vanilla extract and salt.
2. With a wooden spoon, stir the flour into the creamed ingredients, about one third at a time, until evenly blended.
3. Divide the dough in half. Flatten each portion into a disk and seal in plastic wrap. Refrigerate overnight.
4. To create the cookies: Heat the oven to 375 degrees. Cover a sturdy baking sheet with aluminum foil and lightly coat the foil with cooking spray. Between two sheets of waxed paper lightly dusted with flour, roll the dough to a 1/4-inch thickness. Remove the top sheet.
5. Cut out the cookies with a large cookie cutter or a round biscuit cutter. Use a lightly floured spatula to transfer the shapes to the baking sheet, leaving about an inch between cookies. Remove the centers of the cookies with a smaller cookie cutter.
6. Place a pinch of crushed hard candy into the center of each cookie and bake until the cookies start to brown lightly around the edges and the candy is melted, about 8 to 10 minutes. Let the cookies cool on the baking sheet for 5 minutes, then transfer to wire racks to cool completely. To prevent sticking, line your serving plate or tin with waxed paper and place additional waxed paper between layers.