1. Cook onion in oil (or cook with vegetables).
2. Cook vegetables (or use leftovers). Drain well.
3. Grease round pie pan or 8 x 8 inch baking dish.
4. Spread cooked vegetables in pan. Spread cheese on top of vegetables.
5. Mix milk, eggs and baking mix. Pour over vegetables and cheese.
6. Bake at 350 degrees F for 35 minutes, until a safe internal temperature has been reached and a knife inserted into the middle comes out clean.