What you’ll need:
8 slices, whole-wheat bread
1/2 cup chocolate-hazelnut spread, such as Nutella
1/2 cup of smooth peanut butter
8 tablespoons (4 ounces) unsalted butter, softened
Spread the Nutella over 4 slices of the bread, and the peanut butter over the remaining 4 slices. Press the Nutella slices against the peanut butter slices to make 4 sandwiches.
Heat a panini press on high or heat a cast-iron skillet over medium. Spread some butter on one side of each sandwich and place on the panini press, buttered side down. Press until golden brown, about 3 minutes. Spread the remaining butter on the bread facing up, flip the sandwiches, and continue cooking until golden brown. Remove from the heat and eat immediately. If cooking the sandwich in the pan, cook for the same amount of time while pressing down with a weight or a spatula.