Melt butter in a medium saucepan. Don't let the butter brown.
Cook flour and butter for 3-4 minutes to remove the floury taste.
Whisking constantly, stream in heated cashew milk.
Whisk often to avoid sticking to the bottom of the pan. Let sauce cook and thicken, usually about 10 minutes, until sauce coats the back of a spoon.
Add cheese, large handfuls at a time, melting the cheese between additions.
Cook along for another few minutes until nice and thick.
Taste the sauce for salt. Always taste first because different cheeses have different salt content.
Add pepper to taste.
Heat tortillas, one at a time in a dry pan over high heat. If you have a gas stove, tortillas can be heated directly over open flame for a few seconds.
Spread a few tablespoons frijoles in the center of the tortillas shell. Add as much of your filling as you like.
Roll tortilla and place seam side down on serving plate. Top with cheese sauce and any toppings that you like.
sliced black olives
sliced green onion
sliced fresh or pickled jalapenos
sour cream or creme fraiche
Cheese sauce can be stored in refrigerator for 3-4 days.Reheat in microwave or, covered, in 350°F oven for about 25 minutes, until hot.For longer storage, freeze up to 6 months.Thaw in refrigerator. Reheat per above instructions.