**Preheat the Oven**: Set your oven to 350°F.

**Make the Simple Syrup**: Mix the sugar and water in a microwave-safe bowl. Microwave for 90 seconds or until the sugar dissolves completely. Stir in almond or vanilla extract if you like, or leave it plain.

**Prepare the Almond Filling**: In a bowl, mix almond flour, softened butter, granulated sugar, egg, almond extract, and vanilla extract until smooth and well combined.

**Slice the Croissants**: Cut each croissant in half horizontally to create a pocket for the filling. Lightly brush the inside of each half with simple syrup.

**Fill the Croissants**: Spread the almond filling generously on the bottom half of each croissant. Save a little almond filling for the top. Add pieces of chocolate on top of the filling, then place the top half of the croissant back on.

**Add Toppings**: Spread a bit of almond filling on the top middle of each croissant. Sprinkle with sliced almonds, pressing gently so they stick during baking.

**Bake**: Place the croissants on a parchment-lined baking sheet. Bake in the preheated oven for 12-16 minutes, or until the tops are golden brown.

**Drizzle and Dust**: Melt the chocolate in a microwave-safe bowl at 50% power, in 30-second intervals until smooth. Drizzle over the baked croissants. Let them cool slightly, then dust with powdered sugar for extra sweetness.