Cook pasta as directed on package. Drain and set aside in a large bowl. Cover so it won't dry out.
Grind cashews in food processor on high speed until relatively smooth. It's okay if the result is rather grainy looking, so long as what you have is mostly a thick paste.
With processor on low speed, slowly add in the entire can of coconut milk.
Dissolve the bullion cube in the hot water completely. Again with processor on low speed, slowly pour into the cashew/coconut milk mixture to incorporate fully.
Add in the garlic and blend.
Still on slow speed, add in the nutritional yeast, 2TB at a time. Taste after each 2TB to determine the taste that suits you. More nutritional yeast = more cheddar-y type flavor, however, some people do not like the yeast-y flavor it can impart. Add in as much or as little as suits you.
Add in the vinegar the same way, starting with about 1TB, then adding in more 1tsp at a time, tasting after each tsp to determine what you like. The more vinegar you add, the more "sharp" taste you get. For a very sharp taste, try white vinegar.
Salt and pepper to taste.
Once the sauce is at your satisfaction, pour over the pasta and mix well. Add in water (or make some additional broth) if you prefer a thinner sauce. Refrigerate any leftover sauce.
I coupled this with some braised spinach (2 bunches of fresh spinach coarsely chopped and sautéed in 2TB olive oil over medium heat for about 3 minutes), that I threw right into the bowl (you can see the spinach in the picture above). Other veggies that would probably pair nicely: peas, braised julienne carrots, steamed broccoli, steamed asparagus tips.