Made with water, wheat beer, aged gouda and sharp cheddar -- and perhaps more importantly, sodium citrate and iota carrageenan. Recipe via Modernist Cuisine (Vol. 3 p. 387).
Once made, its totally stable, processed cheese, that you can freeze and use quickly whenever you want — melts and emulsifies exactly like Velveeta®, but made with high quality gourmet cheese. Better living through chemistry!
We used some of ours (see inset photo) with the actual pasta from crappy store-bought boxed mac&cheese for kicks.