1) Pour ale beer into a large cup and stir to remove as much carbonation as possible.
2) In a medium pot over medium heat, add butter and melt. Once melted, add flour and whisk to combine. Cook for 2-3 minutes until roux turns a light tan color.
3) Slowly whisk in beer. It should thicken almost immediately as you whisk it in. If it’s a little watery, continue to cook the sauce until it is the consistency of a light gravy. It shouldn’t take more than a few minutes.
4) Add cheese and whisk until melted. Season with salt and hot sauce.
5) Pour into a large bowl and garnish with finely chopped scallions. Serve immediately with hard pretzels.