In a microwave safe bowl, melt butter in the microwave.
While the butter is melting, stir together whole wheat flour, corn flour, baking powder, and powdered butter milk in a large mixing bowl. Add in the butter, milk and egg. Stir until just combined, the batter will be thick.
Line a mini muffin pan with mini muffin wrappers or grease the pan.
Scoop 1 teaspoon batter into each muffin wrapper. Press one blackberry into the top of each muffin. Sprinkle raw sugar over the top of the muffins.
Bake for 12 minutes at 375 degrees. Allow to cool and enjoy!