Preheat the oven to 160C/Gas3; grease an oven proof dish with butter
Cook the pork sausages in the oil over medium heat until golden brown and cooked through; remove from the heat and allow to cool before slicing; fry the mushrooms in the oil in the same pan until done, about 5-7 minutes; remove from the heat and set aside
Spread the slices of bread with the 45g butter and pack the bread slices, overlapping, into the oven dish; tuck the cheese, mushrooms and sausages in between the bread slices
Whisk together the eggs, milk, cream and parsley and season to taste; pour this savoury custard into the dish over the filling and set aside to soak for a couple of minutes
Place the oven dish in a larger oven dish filled halfway with boiling water and bake in the oven until the custard is set – about 40 minutes
Remove from the oven and serve
6 servings