Preheat and Prep: Preheat oven to 350℉ (175°C) and line a muffin tin with 12 paper liners.

Prepare Vegetables: Place grated carrot and zucchini in a clean kitchen towel or paper towel and squeeze out as much moisture as you can. This is a crucial step to prevent soggy muffins.

Combine Wet Ingredients: To a large bowl, add the squeezed carrot and zucchini, chopped spinach, eggs, oil, milk, and tomato paste. Whisk to combine.

Add Seasonings: Mix in the garlic powder, dried oregano (or Italian seasoning), baking powder, baking soda, and salt.

Add Flour: Add the flour and mix in with a large spoon or rubber spatula until just combined. Be careful not to overmix.

Add Cheese and Pepperoni: Mix in ¾ cup of the shredded mozzarella and most of the chopped pepperoni (if using), leaving some to decorate the top of the muffins.

Divide Batter: Evenly divide the muffin batter between the muffin tins, filling each liner about ¾ full.

Top Muffins: Top each muffin with a sprinkle of the remaining ½ cup of cheese and a few pieces of pepperoni, if using.

Bake: Bake until a toothpick inserted into the center of a muffin comes out clean, 18 to 20 minutes. You can also use a kitchen thermometer to check for an internal temperature of 200℉ (93°C).

Cool: Allow the muffins to cool in the pan for 5 minutes, then transfer them to a cooling rack to cool completely.

Store: Store the muffins in an air-tight container in the fridge for up to 5 days or in the freezer for up to a month.