Allow butter to soften at room temperature.

Warm the mixing bowl under running hot water for ten seconds.

Beat softened butter in the warm mixing bowl with the paddle attachment until the consistency is of mayonnaise.

Add powder sugar and combine on low speed, then increase speed and beat until fluffy.

Combine the almond meal and all purpose flour thoroughly in a small bowl, break up any lumps.

Add half the almond meal mixture to the butter, mix on low speed until completely combined, add the rest and mix on low speed again until completely combined. Scrape the side and bottom of the bowl as necessary.

In a small bowl, add egg and almond extract, whisk to combine slightly.

Pour egg mixture into the mixing bowl and beat on low until completely combined and smooth.

Refrigerate mixture for at least 2 hours.

Preheat oven to 350°F.

Add the sliced almond to a plate in an even layer.

Slice the croissants in half, spread about 3 tablespoons of almond cream on the bottom halves, replace the top halves and spread about 1 tablespoon of almond cream on top.

Flip the croissant over and dip the outer surface with the almond cream into the plate of slice almond.

Press it lightly to flatten and to allow almond slices to adhere to the almond cream.

Flip the croissant on its back and on to a parchment line baking sheet.

Bake for 20 minutes.

Remove from the oven and allow to cool on a wire rack.

Dust generously with powder sugar.