Place the eggs in a single layer in a saucepan and cover with cold water. Bring the water to a full boil, cover with a lid, remove the pan from the heat and let sit covered for 12 minutes. Remove the eggs from the pan and submerge in cold water. Crack and peel each egg while still warm.
Toast each slice of bread and spread with the butter. Mash the avocado until smooth and season generously with salt and pepper. Spread the mashed avocado over the buttered toast. Slice the hard boiled eggs and place on top of the mashed avocado. Season once again with salt and pepper and garnish with hot sauce, if desired.
Baby version: Removed yolks from the hard boiled eggs and crumble with your fingers. Mix with the diced avocado and serve.