Line a 15 inch x 10 inch pan (must be at least an inch deep) with aluminum foil. Generously coat with nonstick spray.
In a medium bowl, beat together flour, milk, butter, egg and salt (if desired) until well blended. Pour mixture into the pan. Sprinkle with ham and onion.
Bake for 15 minutes until eggs are set. Immediately sprinkle evenly with cheese and spinach.
Once the cheese has melted, roll the omelet up. Start at the narrowest end. Use the foil to lift and roll. Cut into slices and serve.
Lots of cheese is what makes it cheesy.
Mr Breakfast would like to thank leprican_katie for this recipe.
