In a small saucepan over medium heat, combine the beans, cumin, coriander and ¼ cup water. Cook, mashing with a potato masher, until the beans are hot, well mashed, and thickened to a spreadable consistency, about 3 minutes. If a smoother consistency is desired, use an handheld blender. Add sour cream, green onions and lime juice.Season to taste with salt and pepper. Set aside.
Huevos Rancheros
Preheat the oven to 300 degrees F.
Place tostadas on a baking sheet.
Place in the oven for 5 minutes (you just want to warm them).
Add butter to a nonstick skillet over medium heat. Working in batches, crack the eggs into the skillet. Cook until the bottoms are set, 1 to 2 minutes. Turn the heat to medium-low, cover and cook about 1 minute more (or cook longer to your desired doneness).
Spread about 2-3 tbsp of black bean mash over each tostadas.
Place one egg over each tostadas and top with cheese, tomato salsa, avocado slices and a dollop of lime sour cream. Sprinkle with cilantro and green onions. Squeeze some lime juice over if desired.
Recipe by Valerie's Keepers at https://www.valerieskeepers.com/huevos-rancheros/