Let potatoes cool and cut them into 1 inch thick slices.
Make the sauce by blending cheese, garlic, milk, chiles, crackers, salt and pepper in a blender. The sauce should be thick with the consistency like heavy cream.
Add a little extra milk to thin it out, if needed.
Arrange potatoes in a serving platter and cover with sauce.
Decorate with slices of hard-boiled eggs and black olives.