Place all of the ingredients into a medium-sized saucepan and simmer on low for 5-8 minutes.
Make the taco cups
Preheat the oven to 375°F. Generously coat a 6-well muffin tin with cooking spray.
Drain the black beans and set aside.
Cut the Mission Gluten Free Soft Taco Tortillas into squares and cut each large square into 4 smaller ones. Line each well of the muffin tin with 2 squares of tortilla (one slightly overlapping the other so the bottom of the muffin well is completely covered.) Fill each well with 2 tablespoons drained black beans and a teaspoon or two of cheese. Top each well with 2 more tortilla squares, pressing down gently to compact the bottom layer. Add another tablespoon of black beans and a generous sprinkle of cheese on top of each tortilla cup.
Brush the exposed part of the tortillas with the beaten egg white and bake in the preheated oven for 18-20 minutes.
Don't throw away those tortilla scraps! Toast them in the oven or fry them in a bit of oil to make crispy tortilla strips for topping salads, soups or for snacking!