Preheat oven to 375 degrees.
Spray muffin tins with cooking spray (I use Pam)
Whisk together dry ingredients including rosemary.
Stir in corn kernels.
Combine buttermilk, egg, and oil in a small bowl and then add to flour.
Stir just until combined.
Spoon batter into muffin cups.
Optional-sprinkle with minced rosemary.
Bake 15 to 18 minutes or until tops are golden and a toothpick inserted into center of muffins comes out clean. Let cool in tin or on a wire rack.Serve warm or at room temperature.
Muffins can be stored in an airtight container for several days or frozen for up to two months.