Preheat oven to 325°F.

Line two baking sheets with parchment paper.

In a medium bowl, whisk together: cake flour, baking powder, salt and set aside.

In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar on medium speed for 5 full minutes, until very pale, fluffy, and almost mousse-like.

Mix in: egg whites, heavy cream, sour cream, vanilla, almond extract and beat until completely smooth, scraping down the bowl as needed.

Using a 2-tablespoon cookie scoop, portion the dough onto the prepared baking sheets, leaving about 2½ inches between each cookie.

Lightly dampen your fingertips and gently flatten each mound into a thick disc about ½ inch tall.

The tops should remain pale, and only the very bottoms should show the slightest hint of golden color.

They may look slightly underbaked in the center...that's exactly what you want.

As soon as the cookies come out of the oven, loosely tent the baking sheet with aluminum foil for 8–10 minutes.

The trapped steam gently finishes baking the cookies while keeping them exceptionally soft and moist.

Transfer to a wire rack and cool completely.

Beat the butter for 4–5 minutes until it's very light and fluffy.

Gradually mix in the powdered sugar.

Add: heavy cream, vanilla bean paste, pinch of sea salt then continue beating for another 4–5 minutes until the frosting is smooth, airy, and spreadable.

If desired, tint with a small amount of gel food coloring.

Spread a generous layer of buttercream over each cooled cookie using an offset spatula or butter knife.

Immediately decorate with patriotic sprinkles before the frosting sets.

Allow the cookies to sit for about 30 minutes so the frosting can develop a light crust while remaining creamy underneath.