cup canned chopped tomato (lightly drained, if using fresh, double the quantity)
Break eggs into a bowl. Add salt and pepper and beat well. Pour into a glass measuring cup.
Put 2 T of oil in a medium sized frying pan and set over high heat. When the oil is hot, put in the mustard seeds - as soon as they begin to pop (just a few seconds) put in the garlic.
Stir once or twice. As soon as garlic starts to brown, put in the mushrooms and stir till mushrooms lose their raw look.
Turn heat to medium and put in the scallions, green chile, cilantro, ginger. Stir till the green seasonings have wilted - about a minute.
Put in tomatoes and a little salt and pepper. Stir for 30 seconds (or for fresh tomatoes, till they are no longer watery) and turn off heat.
Put 1 T of the oil in a 7-inch nonstick frying pan (or just spray it with cooking spray) and set over high heat.
When hot, pour in half the beaten eggs. Using a wooden spoon or the back of a fork, stir the eggs for the next 3-4 seconds till they look like lumps of soft custard held together in one unbroken layer.
Quickly spread half the filling along the center of the omelet and fold it over.
Cook for a few seconds and flip omelet over onto a warm plate. Make the second the same way.