Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.
In a large bowl, cream together butter and sugar until light and fluffy. Beat in egg and almond extract.
In a separate bowl, whisk together flour, almond flour, and salt. Gradually add to the wet ingredients, mixing until just combined.
In a small bowl, combine almond paste, softened butter, and powdered sugar to create the filling.
Roll the dough into small balls. Flatten each ball slightly and place a small amount of almond filling in the center. Fold the dough over the filling and pinch to seal.
Place cookies on the prepared baking sheets and bake for 10-12 minutes, or until lightly golden brown.
Let cookies cool on the baking sheets for a few minutes before transferring to a wire rack to cool completely.
Notes
Enjoy these delicious almond croissant cookies with a cup of coffee or tea.