Makes about 3 dozen.
1 cup (2 sticks) butter, at room temperature, plus extra for chocolate dipping sauce
1 cup sugar
1 egg yolk
2 teaspoons freshly grated orange zest
2 cups flour, plus extra for rolling dough
¼ cup orange marmalade, divided
6 ounces bittersweet chocolate
Preheat oven to 375 degrees and line baking sheets with parchment paper.
In a bowl of an electric mixer on medium-high speed, beat butter until creamy, about 1 minute. Add sugar and beat until light and fluffy, about 2 minutes, scraping sides of bowl occasionally. Add egg yolk and orange zest, and beat until thoroughly combined. Reduce speed to low, add flour and mix until just incorporated.
On a lightly floured work surface, using a lightly floured rolling pin, roll dough to 1/4-inch thickness. Using a 1 ½ -inch round cookie cutter, cut dough into rounds, and place cookies 1 inch apart on prepared baking sheets. Repeat with remaining dough, gathering up scraps, re-rolling and cutting until all dough is used. Using your thumb, make a slight indentation in center of cookie and fill with ¼ teaspoon orange marmalade. Bake until edges are lightly browned, about 12 minutes. Remove from oven and cool 2 minutes before transferring cookies to a wire rack to cool completely.
In a double boiler over gently simmering water, melt chocolate, whisking in enough butter (1 tablespoon at a time, up to about 4 tablespoons) to make a good dipping consistency. Dip half of each cookie in chocolate and place on wax paper until chocolate sets.
2007 Winner: Eileen Troxel of St. Paul, Minnesota, who adapted recipe from Traditional Home magazine