Put a piece of puff pastry big enough to fit your apple slice on your work surface and brush with some water. Put one slice of apple on your puff pastry and fill it with your almond paste mixture. Cover the apple slice with another piece of puff pastry and make sure to tightly seal the edges around the apple slice. Use a (scalloped) cutter to cut out the puff pastry covered apple slice, make sure there’s some puff pastry left around the edges that’s sealed to ensure no oil can get into the pastry.