Mix together flour, baking powder, sugar, and salt.
In another bowl, whisk eggs, milk, and peanut butter until blended. Stir into dry mixture until well incorporated.
Stir in butter just before cooking.
Lightly grease waffle iron, if needed.
Pour batter into waffle iron (the amount will depend on the size of your iron). Using a small teaspoon, dollop jam or jelly in multiple places on top of the batter. Add additional batter to cover the jelly. Close waffle iron and cook as usual.