Preheat oven grill to high. Add bacon to a large cold ovenproof frypan and place over medium heat. When bacon begins to sizzle, cook, stirring, for 6 minutes or until crisp. Drain fat, reserving 2 tbs in pan. Add garlic, thyme, mustard and season with pepper. Cook, stirring, for 1 minute or until fragrant. Add the beer, increase heat to medium-high and simmer for 2 minutes or until slightly reduced. Add pasta, milk and 11/3 cups (330ml) water, then stir through flour. Cook, stirring occasionally, for a further 6-8 minutes until almost tender. Stir in half the cheese, then top with remaining cheese. Grill for 3-4 minutes until golden. Sprinkle with parsley to serve.