Pour 1 Tbsp vegetable oil in a large skillet and sauté the onion and mushrooms until tender. Add in the spinach and ham. Continue to cook and stir mixture until the excess moisture evaporates. Allow to cool slightly. Beat in the eggs and then add cheese, spinach and pepper, making sure to blend well.
Spread mixture evenly into a greased 9 inch pie plate or quiche dish and bake at 350 degrees 40-45 minutes or until a knife inserted near the center comes out clean.