Irresistibly Easy Almond Croissant Recipe for Home Chefs

Name: Irresistibly Easy Almond Croissant Recipe for Home Chefs
Ingredients: 6 pieces large croissants (one-day-old croissants left uncovered overnight); 1 tablespoon diced almonds (about per croissant); powdered sugar (for dusting); 3/4 cup water (for simple syrup); 3 tablespoons rum (or vanilla extract for non-alcoholic version); 2 tablespoons granulated sugar (for syrup); 1 cup almond flour or almond meal (for filling); 1/2 cup granulated sugar (for filling); 1 stick salted butter (softened); 1 piece egg (to bind the filling); 1 teaspoon almond extract (for flavor)