2 tablespoons butter, plus more for greasing the pan
Kosher salt
1 head green cabbage
2 tablespoons all-purpose flour
1 cup milk
Freshly ground black pepper
One 15-ounce jar processed cheese sauce or dip, such as Cheez Whiz
1 cup grated pepper Jack cheese
1 jalapeno pepper, sliced into rounds, seeds removed
Paprika, as needed