Preheat the oven to 375°F (190°C).

In a saucepan, combine sugar, water, and 1/2 teaspoon almond extract. Heat until the sugar dissolves.

Slice the croissants in half.

In a bowl, mix softened butter, 1/2 cup sugar, almond flour, egg, 2 teaspoons almond extract, and vanilla extract until smooth.

Spread the mixture on each half of the croissants.

Press the sliced almonds into the mixture on the croissants.

Bake in the preheated oven for about 13 minutes, or until golden brown.

Dust with powdered sugar before serving.