For the Nutella Nut Hearts, roll out the puff pastry and carefully spread with Nutella up to the edges. Then sprinkle evenly with chopped nuts.
Roll up the pastry from both sides until the two rolls meet in the middle. Cut this double roll into slices about 1 cm thick.
Place the slices on a baking sheet lined with parchment paper, pulling the center outward between the two rolls to form a heart.
Spray with a little water and bake at 180 °C hot air until they Nutella Nut Hearts are nice and golden brown (takes about 15 minutes).