Melt butter over a low heat. Add onions, cook, covered for 15 minutes. Uncover and cook for 30 to 40 minutes more until onions turn deep gold. Add stock and nutmeg. Cover, bring to a boil. Reduce heat. Simmer for 15 minutes.

In a small pan, bring beer to a boil over a medium heat. Let beer reduce by half. Remove from heat, add sharp Canadian Cheddar cheese, stir until melted.

Put in blender; add 1 cup (250 mL) of onion soup, blend until smooth. Set aside. Take onion soup off heat and strain. Reserve liquid.

Transfer onions to food processor and purée until smooth. Return purée to the pan and add reserved liquid and Sharp Canadian Cheddar mixture. Season with salt and pepper. Serve very hot.