Over medium heat, melt butter in a saucepan or Dutch oven. Once melted, add the finely diced onion and cook until the onions are translucent, roughly 3-5 minutes.
Once onions are cooked, add flour and stir until onions are fully-coated. Cook for 15-30 seconds. Add chicken stock, heavy cream, garlic powder, salt, and pepper. Stir until well-combined. Allow ingredients to cook together and thicken for about 5-8 minutes.
Add in shredded cheddar cheese and beer and stir well. Cook until heated through and uniformly melted and smooth, roughly 2-4 minutes. If you want the soup to be thinner, add more cream.
Serve in a bowl topped with chopped bacon and chives (either fresh or freeze-dried). Enjoy!
Notes
If you want the soup to be thinner, add more heavy cream.
Be sure to use an amber or pale ale for this recipe. While many other beers would work, I recommend not using an IPA.