Melt the butter over medium-low heat in a saucepan. Sauté the garlic until softened and add the thyme, sage, and flour.
Add the beer, brown sugar, and cinnamon. Bring the mixture to a simmer and cook, stirring occasionally until a bit thickened. Turn down the heat.
Whisk the eggs and milk or cream together in a separate bowl. Add this into the saucepan, bringing the heat back up until the mixture thickens again. Stir in the salt and pepper. You can also stir in 15 ounces shredded sharp cheddar cheese if desired. Let thicken and remove from heat completely.
To serve, toast slices of bread with butter. Place the toast in shallow bowls and ladle soup over the toast until the bread is submerged!