Butter one side of each slice of bread, a generous teaspoon per slice.
On half of the bread slices, on the unbuttered side, spread a generous amount of fermented cashew cheese, 3 to 4 tablespoons (enough to generously cover each slice).
Add 1 tablespoon chili crisp (less for mild heat) on top, but strain it first so you get the crispy stuff and minimal oil; use a clean spoon each time you dig in so you don’t contaminate it. Add your toppings of choice, followed by the shredded cheese (if using), about ¼cup (21 g) per slice.
Top with the remaining slices of bread, buttered side facing up. Flip the sandwich over so that the side with the shredded cheese faces down.
Add one sandwich to a cold medium skillet, or two sandwiches to a cold large skillet (starting with a cold pan helps with slow, even cooking so your bread doesn’t burn before the cheese melts).
Turn the heat to medium, cover with a lid, and cook for 4 to 5 minutes (the steam helps the cheese melt better, but check the bottom occasionally—if the bread is browning but the shredded cheese isn’t near melting, reduce the heat). Flip, cover, and continue to cook until the other side is golden brown, 2 to 3 minutes. If not done yet, flip again, and cook, uncovered, until the second slice of bread is golden brown on the bottom, 1 to 2 minutes.
For the next sandwiches, wipe out the pan and reduce the heat to medium-low to prevent burning and cook for about 3 minutes per side.
Transfer the grilled cheeses to a sheet of parchment paper to prevent sogginess. Serve warm.