Thoroughly wash the spinach to remove any dirt or sand, then dry it completely. Trim the stems and finely chop the leaves.
Boil 2 cups of water in a pan and add all the chopped carrots, beans, onion & peas to it. Allow them to cook till tender - about 5-7 minutes. Drain water in a glass bowl and use it as stock for soups and curries. Set aside the parboiled vegetables.
In a large bowl, sift together the flour, baking powder, baking soda, red chili flakes, and pepper powder. Add the chopped spinach, sun-dried tomatoes, feta, and 2 tablespoons of parmesan, then stir to combine.
In a separate bowl, whisk together the milk, yogurt, and melted butter until smooth. Pour this into the flour mixture and gently fold with a spatula until just combined.
Add in parboiled veggies to the prepared mixture.
Fill each muffin cup about three-quarters full, then sprinkle the remaining parmesan on top.
Bake for 20-22 minutes, or until a toothpick inserted in the center comes out clean. Transfer the muffin pan to a cooling rack and let the muffins cool.