Preheat the oven to 350 degrees F (175 degrees C). Line two baking sheets with parchment paper.
In a medium bowl, whisk the flour, baking powder, baking soda, and salt together. Then set aside the flour mixture.
1 3/4 cups (219 g) all-purpose flour, spooned and leveled, 1/2 tsp baking powder, 1/2 tsp baking soda, 1/2 tsp salt
In a large bowl, cream the butter, brown sugar and granulated sugar together with an electric hand mixer on high speed until fluffy, about 2 minutes. (You can also use the bowl of a stand mixer fit with a paddle attachment.)
3/4 cup (168 g) unsalted butter, softened, 3/4 cup (165 g) light brown sugar, 1/4 cup (50 g) granulated white sugar
Add in the egg yolks, vanilla and almond extract and mix together on medium speed until pale in color and fluffy. (Scrape the sides of the bowl as necessary.)
2 egg yolks, at room temperature, 1 tbsp vanilla, 2 tsp almond extract
Add the flour mixture and ground almonds to the wet ingredients and mix on low speed just until combined.
1/2 cup (54 g) ground almonds
Scoop the cookie dough with a large, 2 tablespoon capacity cookie scoop into 18 portions. (I slightly of overfill my scoop.) Roll each into a ball and use a 1/2 tbsp to make a slight indent in the dough. Add 1/2 tbsp of frangipane to the center of the dough and slightly flatten it out. Top with sliced almonds.
1/2 cup (50 g) sliced almonds, for topping the cookies
Bake 6 cookies at a time, spaced 2 inches apart on a prepared baking sheet. Bake for 12-13 1/2 minutes until they are a light golden brown.When the cookies are straight out of the oven, scoot a large circular cookie cutter around them to give them a perfect circular shape. (They will spread while they bake, so scooting a cookie cutter around them is imperative to get the right shape and thickness.) After baking, let the cookies cool on the cookie sheet for five minutes then transfer them to a wire rack to completely cool. Once cooled, dust each cookie with powdered sugar, then serve!
powdered sugar, for dusting the cookies