Using a standup mixer with paddle attachment, mix the butter and sugars on medium speed for about 90 seconds. Add egg, egg yolk, almond and vanilla extracts. Mix on low speed until combined.
Sift all dry ingredients into a medium bowl. Give the dry mix a good whisk or two so everything is combined. Add the dry to your butter and sugar mixture. Mix on low until flour is barely combined.
At this point, I like to scoop, cover and chill my dough in the fridge for 24 hrs. You can also bake right away if you are short on time. Using an ice cream scoop or large spoon, form dough into about 14 large cookies (or 24 medium cookies), depending on size.
For the almond filling, using a hand mixer or whisk, mix butter and sugar in a medium bowl. Add the remaining ingredients and mix until everything is thoroughly combined. Scoop the mixture into balls. Place the almond balls on a plate and chill in the fridge for about 30 minutes.
When ready to bake, preheat oven to 350 degrees. Important Note: Let your cookies and almond balls sit on the counter for about 20 minutes before stuffing and then baking. Place 3-4 cookies on a baking sheet lined with parchment paper.
Using your thumb, press each ball of dough inward and place a ball of the almond filling into the hole of the dough. Mold the dough around the filling, then roll the cookie dough through the almonds. Press more almonds on top as needed. Bake for about 12 for smaller cookies, 14 – 15 minutes for larger cookies, or when edges browning and tops are slightly brown. Remove from oven, add a few more almonds if you would like. Once cool, top the cookies with powdered sugar.
