Lay out your egg roll wrappers on a clean work surface. Working one at a time, place about a teaspoon of chocolate hazelnut butter in the center of the square. Dip your finger in water and moisten two edges of the wrapper. Fold the other side over to create a triangle, and press the edges to seal in the chocolate. Place another dab of water in the center of the triangle and fold in the long sides to create a little pillow. Repeat with the remaining wrappers.
In a large pan, heat butter over medium heat. As the butter melts, swirl it a bit to make sure it coats the bottom of the pan. Allow it to cook until foamy. Use a heatproof rubber spatula to push the butter around until it begins to brown and smell nutty. Add the chocolate hazelnut pillows in an even layer and allow to cook until brown and slightly crispy, 1-2 minutes. Carefully flip over and continue to cook until crispy on both sides, another minute or two.Transfer the pillows to a plate (being sure to cover them with all that good butter) and dust with powdered sugar if desired.