Put potatoes in a pot, cover, and boil. Cook as many potatoes as there is people being served.
Cut feta into chunks.
Add cheese to blender.
Add 1/2 a can of evaporated milk.
Add 1/4 cup of olive oil.
Add a spoonful of aji amarillo (or to taste).
Blend in a blender.
Add to taste.
Pour into bowl.
Put in fridge for a few hours.
Cut boiled potato in 1/2 and put sauce on potato.