Add eggs, milk, salt and pepper in a bowl. Mix well.
Then, add onions, tomatoes, chopped basil leaves in a baking quiche mould and pour the egg mixture on it.
Garnish it with tomato slices and grated parmesan cheese.
Meanwhile, add water in the inner pot of instant pot and place trivet in it.
Place the quiche mould on the trivet and close the lid.
Press the “Manual” button and cook for about 20 minutes on HIGH pressure.
Release the pressure naturally through the steam vent and open the lid.
Take out the quiche and serve hot.