Recipe by David Lebowitz
These now-classic French pastries are made in bakeries using day-old croissants. At home, you can use whatever croissants you can get your hands on. They don’t need to be extra fancy, but you do want to use ones made with pure butter, which have the best flavor.
The liquor is a nice addition to the syrup, but if you’re avoiding alcohol, a small amount of orange flower water is a good substitution, or you can infuse a vanilla bean in the syrup or add some extract.
Syrup
1/2 cup (125ml) water
1/4 cup (50g) granulated sugar
2 tbsp dark rum, amaretto, or kirsch (optional, but recommended)
Frangipane
1/2 cup (50g) almond flour (powdered almonds)
1/4 cup (50g) granulated sugar
1 large egg, at room temperature
3 1/2 tbsp (50g) unsalted butter, at room temperature
A few drops pure almond extract
Pinch of salt
4x day-old croissants
1/2 cup (40g) sliced almonds
Powdered sugar
Make the syrup by heating the water and sugar in a medium saucepan until the mixture comes to a boil, stirring occasionally. When the sugar is dissolved, remove from heat, let cool to room temperature, then add the liquor.
Preheat the oven to 375ºF (190ºC). Line a baking sheet with parchment paper or a silicone baking mat.
Make the frangipane by beating the almond flour, sugar, egg, butter, almond extract, and salt in the bowl of a stand mixer fitted with the paddle attachment (or by hand) at medium-to-high speed until the frangipane is light and fluffy, about 3 minutes.
Slice each croissant in half horizontally, stopping just before you reach the other side, leaving it with a hinge to open and close it. Place them on the prepared baking sheet. Liberally brush the insides, both top and bottom, with the syrup. You want to make sure both sides are completely saturated with the syrup. Don’t be shy—even if you think it’s too much, really saturate the croissants. French bakers dunk the entire croissant in a big vat of sugar syrup.
Smear the inside of each croissant with 2 tablespoons of the frangipane. Press down firmly on each croissant so the top is relatively flat. Spread the remaining frangipane over the tops of each croissant.
Sprinkle each croissant with 2 tablespoons of sliced almonds and bake the croissants until golden brown, about 15 minutes, but check them a few minutes before the recommended baking time. Let them cool a few minutes, then sprinkle them with powdered sugar. Serve warm or at room temperature.