Preheat the oven to 350 F. Line a 12 cup muffin pan with paper liners. In a large bowl, whisk flour, sugar, salt, and baking powder together. Add in the melted butter, milk, and egg and whisk until smooth.
Fold in the cocoa pebbles cereal. Evenly divide the batter between the muffin pan. Bake for 15-20 minutes.