Melt butter in a skillet over medium heat. Add cauliflower, onions, oregano and garlic. Cook for 5 to 7 minutes, or until veggies are softened. Spread mixture in a 9x13 ungreased casserole dish.
In a bowl, whisk together eggs, Bisquick, milk and cheese. Pour over veggies.
Bake for 40 minutes. Sprinkle with chopped parsley.