Place the refried beans in a small pot or skillet and heat over medium heat until hot.
Heat a large nonstick skillet over medium-high heat and add the butter. Carefully crack the eggs into the skillet, season with salt and pepper and cook until the yolks are done to your liking, 2 to 3 minutes for sunny-side up eggs with still-runny yolks.
To serve, set up 4 plates. Spoon refried beans onto the bottom of each plate and top with a broken taco shell to form a circle. Top each with a cooked egg and avocado, then season with salt. Add some pico de gallo and cilantro. Drizzle with hot sauce if desired.