Place the sugar in a large, shallow dish and pour in the hot water. Whisk in the extract until the sugar has completely dissolved.

Halve the croissants horizontally.

Dip the croissant bottoms quickly in the syrup and place them on a parchment-lined baking sheet.

Preheat the oven to 350 degrees F.

Whip the sugar, butter, and salt together on medium-high speed until very pale and doubled in volume (approx. 5 to 7 minutes).

Mix in the first egg until completely incorporated.

Whip in the second egg, along with the extracts.

Fold in the almond meal and place 2 to 3 tablespoons of the filling on the croissant bottoms, spreading it into an even layer.

Dip the croissant tops quickly in the syrup, then place them on top of the filling.

Spread a thin layer of the filling on top of the croissants.

Top with sliced almonds and bake until the nuts are toasty and fragrant (approx. 15 to 20 minutes).

Dust the tops with powdered sugar.