Preheat oven to 425°.
Whisk together flour, cornmeal, sugar, baking powder, salt, and pepper in a medium bowl; make a well in center of mixture. Combine buttermilk, butter, and egg white in a small bowl; add to flour mixture, stirring until just moist. Fold in feta and corn.
Coat a 20-cup mini muffin pan with cooking spray. Spoon batter into prepared pan; bake
for 10-12 minutes or until muffins spring back when touched lightly in center. Remove muffins from pan immediately; place on a wire rack. Serve warm.