Chocolate-Hazelnut Thumbprints

Ingredients

• 0.5 cup butter softened
• 0.3 cup nutella (such as Nutella)
• 2 large egg yolk 
• 1 cup flour all-purpose
• 0.7 cup hazelnuts toasted finely chopped
• 1 cup powdered sugar 
• 0.3 teaspoon salt 
• 0.3 cup cocoa powder unsweetened
• 0.5 teaspoon vanilla extract 

Equipment

• bowl
• baking sheet
• baking paper
• oven
• knife
• whisk
• blender
• wax paper
• measuring cup

Directions

1. Preheat oven to 35
2. Weigh or lightly spoon flour into a dry measuring cup; level with a knife.
3. Combine flour, sugar, cocoa, and salt; stir with a whisk.
4. Place butter in a large bowl, and beat with a mixer at medium speed until light and fluffy (about 2 minutes). Stir egg yolks with a whisk, adding espresso, if desired.
5. Add the yolk mixture and vanilla to butter; beat well.
6. Add flour mixture to butter mixture; beat at low speed just until combined.
7. Turn dough out onto a sheet of wax paper; knead 6 times or until smooth and shiny. Shape dough into 28 (1-inch) balls.
8. Roll sides of balls in nuts, pressing gently. Arrange balls 1 inch apart on baking sheets lined with parchment paper. Press thumb into center of each cookie, leaving an indentation.
9. Bake, 1 batch at a time, at 350 for 10 minutes.
10. Remove cookies from pans; cool completely on wire racks. Spoon a scant 1/2 teaspoon hazelnut-chocolate spread into center of each cookie.