I think it might depend on the cheese you’re using! In my experience the roux makes a big difference. We use a blend of Gruyere, Fontina and Cheddar (in 1-2-2 proportion). The hard, soft, and middling textures mix best when they’re gently cooked together in our experience.

In the states most recipes will have you finish in a casserole dish with bread crumbs, but we find it actually tastes better if you skip that step, for whatever reason.

If anybody has suggestions on other cheeses to add/substitute in this mix I’m all ears!