Step 1 Melt the chocolate in the top of a double boiler set over, but not touching, simmering water. Remove from the heat. Cut the butter into a few pieces and mix into the chocolate until melted.
Step 2 Beat the eggs with an electric mixer, gradually adding the sugar until ribbons form. Fold in the chocolate-butter mixture. Gently add the ground almonds. Cover and refrigerate overnight.
Step 3Heat the oven to 325 degrees. Line a baking sheet with parchment paper.
Step 4Use a cookie scoop to form the dough into 1-inch balls. Roll the balls in granulated sugar, place on the baking sheet about 2 inches apart and immediately place in the oven.
Step 5Bake until the center of the cookies is no longer wet, 9 to 12 minutes. When slightly cool, lightly dust the cookies with powdered sugar.