Marinate the Chicken:

1. In a shallow bowl, combine the lager, garlic, salt, and pepper. Add the chicken breasts, cover with plastic wrap, and refrigerate for at least 2 hours (or overnight for deeper flavor).
2. When ready to cook, remove the chicken from the fridge and let it sit at room temperature for 20 minutes.

Cook the Chicken:

1. Heat a skillet or pan over medium-high heat. Drain the chicken from the marinade and pat dry. Fry the chicken breasts in a small amount of oil until golden brown on both sides and fully cooked through (about 6-8 minutes per side, depending on thickness).
2. Once cooked, transfer the chicken to a warm plate and set aside.

Make the Sauce:

1. In the same pan, cook the diced bacon until crispy (about 6 minutes). Transfer to a paper towel-lined plate to drain.
2. To the remaining bacon fat in the pan, add the onion and celery, cooking until softened (about 6 minutes). If there is not enough bacon fat, add 2 tablespoons of butter instead.
3. Stir in the garlic and cook for about 1 minute, until fragrant.
4. Pour in the lager and cook until reduced slightly (about 3-4 minutes).
5. Sprinkle in the flour, cooking for about 3 minutes until golden brown. Slowly whisk in the chicken stock, followed by the milk. Simmer, whisking occasionally, until the sauce thickens.
6. Stir in Worcestershire sauce, vegetable stock powder, Dijon mustard, and hot sauce (if using).

Finish the Dish:

1. Remove the sauce from heat and stir in the shredded cheddar cheese. Continue stirring until the cheese is melted and the sauce is creamy.
2. Stir in ¾ of the crispy bacon, reserving the rest for garnish. Taste the sauce and adjust seasoning with more salt, pepper, cheese, or beer if desired.
3. Return the cooked chicken to the pan, spooning the sauce over the top. Let the chicken warm through for a couple of minutes.
4. Garnish with the remaining bacon and freshly chopped parsley or chives.