01 - Set oven temperature to 375°F. Prepare a 12-cup muffin pan with paper liners or grease lightly.
02 - Whisk together flour, baking powder, baking soda, salt, and pepper in a large bowl.
03 - In a separate bowl, beat eggs, milk, and olive oil or melted butter until thoroughly blended.
04 - Add wet mixture to dry ingredients and stir gently until just incorporated to avoid overmixing.
05 - Fold in cheddar, feta, bell pepper, spinach, chives, and parsley until evenly distributed throughout the batter.
06 - Divide batter evenly among muffin cups, filling each about three-quarters full.
07 - Bake for 22 to 25 minutes until tops are golden brown and a toothpick inserted in the center comes out clean.
08 - Allow muffins to cool in the pan for 5 minutes before transferring to a wire rack. Serve warm or at room temperature.