Heat butter and oil in a non-stick or an iron skillet.
Add in chopped garlic, green chillies and onions.
Sauté till onions turns translucent.
Now add in sliced in mushrooms and sauté for 2 minutes.
Add pinch of salt and pepper powder to taste, mix well.
Into a bowl break open 6 whole eggs, add ¼ cup of milk, pinch of salt and pepper powder to taste. Though milk is optional, adding milk makes frittata fluffy.
Whisk everything well together.
Pour over the prepared mushroom and mix well gently with cooked mushrooms.
Grate 25grams of processed cheese.
Sprinkle Italian seasoning and fresh cilantro.
Cover lid and cook on medium heat until base turns firms. Cooking time depends on depth of the pan. . (Alternatively , If baking ,preheat oven to 400°F and place the iron skillet in preheated oven to bake for 15-20 minutes until eggs are firm at bottom and set at top)
After 8-10 minutes, remove lid and check if the base is firm. Turn off stove
Loosen the edges, cover the pan with plate and turn upside down.
Now slide the other side of the egg into pan.
Turn on the stove, keep on simmer and cook for 2 minutes.
Remove frittata from pan, cut into wedges and serve alongside with bread toast.