Preheat oven to 200 degrees C (400 degrees F).
Inside a plastic container, add the Yellow Onion (1), Ham (150 gram), Cheddar Cheese (1/2 cup), and Self-Rising Flour (1/2 cup). Put on the lid over the container and shake until everything is mixed well.
Inside a jug, mix together the Egg (4), and Milk (1/2 cup). Pour the egg mixture into the container. Season with Salt and Pepper (to taste), and stir everything through.
Transfer the mixture into a pie plate, and bake inside a preheated oven under 200 degrees C (400 degrees F) for about 45 minutes.