Take a pan with a lid and put it on the stove on medium flame. Add 1/2 tablespoon of oil.

Add the onions. Saute for a couple of minutes n then add mushrooms and saute for couple more minutes

Add the vegetables and a dash of salt and saute for couple more minutes and close the lid and let it cook for 5-7 minutes

Meanwhile beat the eggs in a bowl with the before ingredients

Remove the veggies from heat and add it to the eggs mixture and a give it a beat. Return the pan to the heat and reduce the heat to less than medium

Add the remaining oil to the pan and evenly spread it just to avoid the omelette sticking to the pan. Now add the beaten eggs evenly in the pan. Sprinkle with half cup of cheese. You can add as much of cheese u like. Close the lid and let it cook for 8-10 minutes

Now you are done. Just take the omelette out as it is, from the pan (dont flip the omelette). Serve it with a toast.