Preheat the Oven: Preheat your oven to 375°F (190°C). Grease or line a 12-cup muffin tin with paper liners.
- Combine Dry Ingredients: In a large bowl, whisk together the flour, baking powder, baking soda, salt, and pepper. Set aside.
- Add Cheese and Olives: Stir in the grated halloumi cheese, chopped green olives, and black olives. This ensures that the cheese and olives are evenly distributed throughout the dry ingredients.
- Mix Wet Ingredients: In a separate bowl, whisk together the olive oil, milk, egg, and lemon zest (if using).
- Combine Wet and Dry Ingredients: Pour the wet ingredients into the dry ingredients and gently fold until just combined. Be careful not to overmix, as this can make the muffins dense.
- Fill Muffin Tin: Spoon the batter evenly into the prepared muffin tin, filling each cup about 3/4 full.
- Bake the Muffins: Bake for 18-22 minutes, or until the tops are golden and a toothpick inserted into the center comes out clean. If the muffins are browning too quickly, cover them loosely with foil and continue baking.
- Cool and Serve: Let the muffins cool for a few minutes in the tin before transferring them to a wire rack to cool completely. Garnish with fresh parsley before serving if desired.