Instructions

1. Add Butter and Sugar to a bowl and beat until well combined.
2. Add Egg Yolk and Vanilla Extract. Beat well.
3. In a separate bowl, combine flour, Cocoa Powder, and Cornstarch. Add the flour mixture to wet ingredients until combined. (The dough may seem dry.)
4. Press dough into a square, cover with plastic wrap and refrigerate for 30 minutes.
5. Use a tablespoon of cookie dough mixture to roll into a ball. (Make sure there are no cracks or seams in the cookie ball.)
6. Roll cookie dough ball in granulated sugar and place on cookie sheet.
7. Use your thumb or the back of a rounded teaspoon to gently press an indent into the top of the cookie.
8. Spoon jam into the dent in your cookies.
9. If the jam is too firm, heat in microwave for 10 seconds, until the jam has loosened up. Do not overheat.
10. Bake cookies in an oven preheated to 375 degrees for 11 mins until the edges of the cookie just start to turn brown.
11. Cool cookies completely before serving.