Preheat your oven to 180°C (350°F) and grease a muffin tin or line with paper liners.
Dice or grate about 1 cup of mixed odds and ends vegetables, like zucchini, bell peppers, and spinach. Squeeze out any excess moisture to prevent sogginess.
In a large bowl, whisk together the eggs, milk, and olive oil until the mixture is smooth and slightly frothy, releasing a lovely aroma.
Add the shredded cheese to the wet mixture and stir until evenly distributed, creating a cheesy, savory aroma.
In a separate bowl, sift together the flour, baking powder, salt, and pepper for a fluffy, well-mixed dry base.
Gently fold the dry ingredients into the wet mixture just until combined—be careful not to overmix to keep the muffins light and airy.
Stir in the chopped vegetables, distributing them evenly throughout the batter for colorful, savory bursts in each muffin.
Spoon the batter into the prepared muffin tin, filling each cup about three-quarters full. Smooth the tops with the back of a spatula for an even look.
Bake in the oven for 20–25 minutes, until the muffins are golden brown around the edges and a toothpick inserted into the center comes out clean with a slight cheesy aroma.
Remove the muffins from the oven and let them rest in the tin for 5 minutes to set. Then transfer to a wire rack to cool slightly and develop a tender, flaky crust.
Serve warm or at room temperature, enjoying the cheesy aroma and colorful vegetable bits in each bite.