Start by preheating your oven to 350°F (175°C). Then, in a mixing bowl, whisk together the flour, baking powder, baking soda, salt, and cornstarch. This step ensures your cookies have the perfect structure. Set this mix aside.

In a large mixing bowl, cream together the unsalted butter and granulated sugar until light and fluffy. This usually takes about 2-3 minutes with an electric mixer. The creamy texture is key to fluffy cookies. Next, add in the egg, egg yolk, and vanilla extract. Mix until fully combined—smooth is what you are going for here.

Gradually add in your dry mix to the wet ingredients. Start with half, mix, then add the remainder. This ensures everything incorporates well. You’ll see the dough come together—it's a beautiful sight.

Using a cookie scoop or your hands, portion out the dough onto a baking sheet lined with parchment paper. Leave space between each cookie, as they will spread a bit. A good rule of thumb is to place them about 2 inches apart.

Pop the cookies in the oven. Bake for about 10-12 minutes, or until they are just set and lightly golden around the edges. They'll look soft in the center—that's exactly what you want!

Once done, let the cookies cool on the baking sheet for about 5 minutes before transferring them to a wire rack. This cooling period helps them set without breaking.

While the cookies cool, whip up your frosting. In a clean bowl, beat together the softened butter, cream cheese, and vanilla bean paste until smooth. Gradually add the powdered sugar, mixing until everything blends into a creamy, dreamy frosting. If you enjoy a hint of nuttiness, throw in that almond extract.

Once the cookies have cooled completely, it’s time to fill them. Frost the bottom of one cookie, then top it with another. Press gently, just enough for the frosting to peek out. You can garnish the edges with sparkling sugar for an extra fancy touch.

Let’s face it—you’ve done an incredible job! Grab a cup of your favorite beverage and dig in.