Spread the bread over a baking tray, drizzle with a little melted butter and grill for around 6 to 7 minutes turning a few times until toasted. Keep aside.
Cook the pasta in salted boiling water for around 6 minutes. Drain and keep aside.
Preheat the oven to 200 degC.
Heat the oil in a pan and add the garlic, shallots, Worcestershire sauce and mustard powder. Stir fry for 1 - 2 minutes and then add the flour. Stir for 1 minute and then slowly add the milk stirring continuously and bring to the boil. Simmer for 5 minutes, stirring constantly until thickened.
Remove from the heat and stir in the grated cheddar cheese.
Add the pre-cooked pasta into the cheese sauce, and season well.
Transfer to an ovenproof dish, spread the toasted bread over the top and bake for in the oven for 20 minutes until golden.