Preheat the oven to 200 degrees Celsius.Line your pie dish with the streaky bacon until covered.Bake in the oven until a little crispy (15 mins plus minus).In the meantime, prepare your ingredients.Beat the eggs with the milk, origanum and salt and pepper.Remove bacon from the oven and drain most of the fat.Reduce oven temperature to 180 degrees Celsius.Place the mushrooms, cheese, and onion in the dish over the bacon.Cover with the egg mixture.Place the slices of tomato on top.Bake in the oven 35-45 minutes (I baked it for 40mins).Remove from the oven and allow to cool a bit before serving.