1. Mix the butter, flour and boiling water until it forms a dough ball. Press the dough onto the bottom and against the sides of a pie dish and place in the fridge.
2. Make the filling Melt the butter in the microwave. Stir in the flour and milk and microwave on high for 3 minutes. Beat in ¾ of the cheese and season to taste with salt and pepper. Preheat the oven to 180°C.
3. Mix the ham, spring onions, rocket and eggs with the cheese sauce and spoon into the prepared crust. Sprinkle the rest of the cheese on top and bake for 40 minutes or until cooked. Cool for 10 minutes before serving.