Preheat the oven to 180C (350F). Line a heavy tray with greaseproof paper. Slice into the bread rolls and remove most of the bread keeping the crust intact. Crack the eggs into a bowl and add all the ingredients. Lightly whisk with a fork until combined. Carefully fill the bread boats with the egg mixture about 3/4 of the way up - the eggs will puff up as they bake and you want to avoid leaks. Bake for 20 minutes keeping an eye on the bread so that it doesn't brown too much (cover with foil if it does). Take out of the oven and rub some butter on the bread crust. Return to the oven for another 5-10 minutes or until the egg is set in the middle. Cool for 5 minutes, season with salt and pepper and serve warm.