Get out a large pot and heat Butter (2 tablespoon) in it over medium-high heat. Brown the first Boneless, Skinless Chicken Thigh (6) it for 5 minutes on each side. On the second side, pour in two tablespoons of the Beer (1 bottle) to cook the chicken in it a little.
Remove them to a plate and add the next Boneless, Skinless Chicken Thigh (6) to the pot. Pour in another two tablespoons of the beer again when they are on the second side. Remove them to a plate when they are done.
Add in the remaining Butter (6 tablespoon) and let it start to melt. Whisk in the All-Purpose Flour (6 tablespoon) until it becomes a paste and just starts to turn golden. Whisk in the Dijon Mustard (2 tablespoon) and a 1/4 cup of the beer and let them cook in for a minute. The remaining beer in the bottle goes to the chef! Then slowly pour in the Milk (3 cup) while you keep whisking until you have a sauce.
Turn the heat to medium-low and let it bubble and thicken for 10 minutes, whisking it occasionally. Finally, whisk in the Cheddar Cheese (12 ounce) and nestle the chicken back into the sauce. Let it bubble together for another 10 minutes.
Serve immediately with the Fresh Dill (to taste) sprinkled on top and your favorite sides. Enjoy!