Break up the almond paste into smaller chunks and place into a food processor along with the granulated butter and sugar.
Pulse until chopped fine. Add in half of the beaten egg and flour, process until smooth.
Lay the puff pastry out onto a lined baking sheet. Spread the almond paste mixture over half of the puff pastry sheet, leaving about an inch around the edges.
Fold the unfilled half of the pastry over the filling, crimp the edges together and roll the edge under the bottom seam to make sure it is sealed.
Make 4 cuts about ¾ of the way through the pastry to form the “claw” (it will make 5 "fingers").
Fan out the pastry slightly to separate the "fingers". Brush with the remaining egg all over and sprinkle the top with sliced almonds and coarse sugar.
Bake at 400°F for 16-18 minutes until golden brown. Allow to cool at least a few minutes before serving.
Calories are automatically generated. For best results calculate based on your exact ingredients.Some filling may seep out, this is expected. Just cut off any excess filling to form a uniform looking pastry before serving, if desired.