In a large pot, melt butter over medium heat. Add the chopped onion and sauté until soft and translucent (about 3-4 minutes). Add the minced garlic and cook for another minute.

Sprinkle in the flour and stir well to create a roux. Cook for 2 minutes, stirring constantly, until the mixture is golden.

Slowly pour in the Guinness while whisking to prevent lumps. Allow it to simmer for 3-4 minutes to cook off the alcohol.

Add the broth, Dijon mustard, Worcestershire sauce, cayenne, nutmeg, and allspice. Stir to combine and let simmer for 10 minutes.

Reduce heat to low and gradually add the shredded cheddar, stirring continuously until melted and smooth.

Stir in the heavy cream and let the soup warm through without boiling. Season with salt and black pepper to taste.

Serve hot with crusty bread or pretzels. Enjoy!