Prepare the Vegetables: Wash and finely chop the vegetables. Grate the zucchini and carrot, then gently squeeze excess moisture from the zucchini.
Prepare the Muffin Pan: Lightly grease a 24-cavity mini muffin pan or use mini muffin liners.
Mix the Dry Ingredients: Whisk the flour, baking powder, salt, and black pepper together in a large bowl.
Mix the Wet Ingredients: In a separate bowl, whisk together the eggs, milk, and olive oil until smooth.
Add the Cheese and Vegetables: Add the cheddar cheese, carrot, zucchini, red bell pepper, green onions, and parsley to the dry ingredients.
Combine the Batter: Pour the wet mixture into the dry ingredients. Gently fold until just combined. Do not overmix.
Fill the Mini Muffin Pan: Divide the batter evenly among the prepared mini muffin cavities.
Bake in a preheated 375°F (190°C) oven for 16–18 minutes, or until lightly golden and cooked through.
Cool and Serve : Allow the muffins to cool in the pan for a few minutes, then transfer them to a wire rack.