Chocolate Chip-Banana Muffins

1 egg
2 cups Original Bisquick mix
1 1/4 cups mashed very ripe bananas (2 to 3 medium)
1/3 cup sugar
3 tablespoons vegetable oil
1/3 cup miniature semisweet chocolate chips

Heat oven to 400 degrees. Place paper baking cup in each of 12 regular-size muffin cups, or grease bottoms only of muffin cups.

Beat egg slightly in medium bowl; stir in remaining ingredients just until moistened. Divide batter evenly among muffin cups. Bake about 15 minutes or until golden brown. Makes 12 muffins