Place a small sauce pot over medium heat. Pour the beer in the pot. Peel and crack one garlic clove; then add it to the pot.
Mix the shredded cheese with the flour and ground mustard. Slowly add the floured cheese to the beer. Whisk until smooth. You will think you’ve made a mistake until the mixture gets hot enough to thicken and come together—just keep whisking! (5-10 minutes) Remove the garlic clove.
Once smooth and thick, pour into a fondue pot and serve! Serve with bread cut into cubes, sliced apples, grapes, gherkin pickles, and boiled baby potatoes.