Using a medium bowl, combine the almond flour and all-purpose flour; set bowl aside.

Using an electric mixer, cream together the butter and sugar until light and fluffy (~2-3 minutes on medium speed).

Add egg, vanilla extract and almond extract; mix on low speed until well combined.

Add flour mixture (from above); mix on low speed until well combined. Set almond filling aside.

Cover with plastic wrap and refrigerate for 30 minutes. (Note: If you haven’t already made the filling, this is a good time to do that.)

Preheat oven to 375°F.

Remove the puff pastry from refrigerator and trim into a 12”x15” rectangle. Transfer puff pastry onto a piece of parchment paper.

Using the back of a dull knife (i.e. table knife), lightly score 2 lines down the length of the dough 4” in from each of the long edges.

Spread the almond filling evenly into the center portion of the dough, leaving ~1” of space at either end.

Using a sharp knife, cut the sides of the dough into 1” strips on a diagonal. Discard the excess triangle of dough from the top and bottom.

Fold the 1” piece of dough at the top and bottom over the filling.

Next, fold the diagonal strips over the dough, alternating between sides to create a braided look.

Using a small bowl, whisk the egg together with 1 Tbsp of water. Brush this egg wash evenly on top of almond puff pastry.

Sprinkle top with sliced almonds and sanding sugar.

Transfer parchment onto a baking sheet. Bake for 25-30 minutes, or until top is golden brown in color.

Let cool on pan for 10 minutes and then transfer to a wire rack until completely cool.

If desired, dust the top of the pastry with powdered sugar.

Cut pastry into 2” strips for serving.