Divide each of the 2 puff pastry sheet into 6 equal rectangles, giving you 12 rectangles in total.

To make the filling combine the almond paste, butter, flower, and ¼ cup powdered sugar in a food processor. Beat an egg in a small bowl, and add half of the egg into the food processor, and save the other half for later. Combine all these ingredients until a smooth almond filling is formed.

Divide the almond paste mixture evenly between the 12 pastry pieces and place it in the center of each rectangle. Fold dough over and seal the edges, using a fork to press down firmly along the edges of dough. Use a sharp knife to make 4 short slits along one side of the pastry, taking care to make sure the edge is still very well sealed so that the filling doesn't seep out of the slits as it bakes.

Brush the pastry with the leftover egg wash, and then sprinkle with sliced almonds, or add one sliced almond to make 5 bear claws. Arrange the bear claw pastry on the baking sheet lined with parchment paper or sprayed with nonstick cooking spray. Place dough with a slight curve, to create the bear claw shape.

Bake in a preheated oven at 400 F for 12 minutes until they are golden brown. Let the pastries cool on a wire rack.

To make the glaze, combine 3 tablespoon powdered sugar, milk, and almond extract in a small bowl and stir until well combined. Drizzle the glaze over the cooled individual bear claws.