Remove the butter from the refrigerator to soften. Place an oven rack in the center of the oven; preheat to 400°F. In a bowl, combine the softened butter, egg, almond flour, vanilla powder, and half the powdered sugar. Using a fork, mash until thoroughly combined (the texture should resemble a smooth paste).

Place the croissants on a sheet pan. Evenly spread the almond cream on top of the croissants. Bake 8 to 10 minutes, or until golden brown and the cream is set. Remove from the oven and immediately top with the almonds. Let stand at least 5 minutes. Serve the baked croissants sprinkled with as much of the remaining powdered sugar as you’d like. Enjoy!