Preheat the oven to 400 degrees F. Cut off the outer edge of each tortilla so that the tortillas fit snugly into the regular muffin tin cup. Brush both sides of the tortillas lightly with melted butter and sprinkle with salt and pepper. Press the tortillas into the muffin tin cup, creating little tortilla cups.
In a small bowl, mix half of the salsa with the black beans with salt and pepper. Spoon a heaping tablespoon of the black bean mixture into each tortilla cut. Crack an egg into each of the eight cups. Bake until barely set, about 8 minutes. Top with cheese, cover with aluminum foil and then back for 6-7 minutes more.
To serve, spoon the sour cream and remaining salsa on top of the eggs.