Cookies

2 cups powdered sugar, divided
1 1/4 cups slivered almonds
3 tablespoons natural unsweetened cocoa powder
1/3 cup plus 3 tablespoons egg whites (from about 3 large eggs), room temperature, whisked to loosen
1/4 cup sugar

Ganache

3 1/2 ounces bittersweet chocolate (do not exceed 61% cacao), finely chopped
2 tablespoons (1/4 stick) cold unsalted butter, cut into 1/2" cubes
1/2 cup heavy cream
1 tablespoon finely grated orange zest
1/2 teaspoon ground cloves
1/8 teaspoon ground allspice
1/8 teaspoon kosher salt
Gold dust (optional)