In a medium pot, heat the butter over medium-high heat and sauté the onions until starting to turn golden. Add the celery and carrot and continue to sauté for a few minutes more. Shake the flour overtop and stir to coat the veggies. Add the beer, stock and cream and simmer until the soup has thickened, about five minutes more. Add the grated cheddar, salt and pepper and Worcestershire sauce and stir until smooth. Serves 4-6.