1. Preheat oven to 400°.
2. Combine buttermilk, olive oil, and egg; stir well with a whisk.
3. Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, cornmeal, sugar, baking powder, baking soda, salt, pepper, and pecorino Romano cheese in a medium bowl, stirring well with a whisk. Make a well in center of flour mixture. Add milk mixture, and stir just until moist. Gently stir in green onions, parsley, and thyme. Spoon into 12 muffin cups coated with cooking spray. Bake at 400° for 13 minutes or until a wooden pick inserted in center comes out with moist crumbs clinging.