Step 1Cook the corn in the butter in a small skillet over medium-low heat until tender, about 3 minutes.
Step 2Combine the flour, baking powder, sugar and salt in a large bowl. Stir in the buttermilk and corn, along with any remaining butter in the pan, until just blended.
Step 3Beat the egg whites in a separate bowl using an electric mixer until stiff but not dry. Fold the egg whites into the batter just until blended.
Step 4Spray a waffle iron with nonstick cooking spray or brush with oil, then heat. Pour about 1 1/4 cups batter into the iron. Close the lid and cook until golden brown, about 8 minutes. Remove the waffle from the iron and break into 4 sections. Repeat with remaining batter. Sprinkle the waffles with powdered sugar.