Start by pouring the 1 cup of water into a small saucepan and adding the 3 tablespoons of sugar along with the 4 tablespoons of rum (or vanilla extract if you prefer). Bring this mixture to a simmer over medium heat. Stir it for a minute until the sugar completely dissolves. Once it’s nicely combined, remove it from heat and set aside to cool to room temperature. This syrup is what transforms the croissants from stale to sensational, giving them all the moistness they'll need.

For the almond filling, it depends on your choice of using whole almonds or almond flour. If using whole almonds, toss 2/3 cup of blanched almonds, ½ cup granulated sugar, and 1/8 teaspoon of salt into a food processor. Pulse until the almonds are finely ground. Next, add in 8 tablespoons of softened butter and mix until the blend is smooth. Add in the eggs one at a time, processing until you achieve that lush, creamy texture.

If you’re opting for almond flour, grab your stand mixer fitted with a whisk attachment. Combine ½ cup sugar, 1 cup almond flour, and 1/8 teaspoon salt. Mix until all is incorporated. Then blend in the softened butter followed by the eggs, one at a time. You'll want to mix this on medium-high speed until it’s creamy and fluffy, similar to frosting. Don’t forget to add the optional teaspoon of almond extract and lemon zest for an extra burst of flavor!

Now, preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. On a clean counter, take your croissants and slice them horizontally as if you’re preparing a sandwich.

Work with one croissant at a time: dip it into the prepared syrup, making sure to coat both sides and the ends. You want it moist—not drenched! After dipping, place it cut side up on the baking dish.

Spread about 2 tablespoons of your almond filling on the bottom half of each croissant. Then, place the top half back on and spread roughly 1 tablespoon of the filling over it. Top with a sprinkle of sliced almonds for added crunch and beauty.

Bake the assembled croissants in your preheated oven for about 15 to 18 minutes, or until they turn a lovely golden color. The smell will be intoxicating! Transfer them to a wire rack and let them cool—just slightly; they are best enjoyed warm. Just before serving, dust with powdered sugar for that extra touch of sweetness.