Cut the potatoes into similar sizes and add enough olive oil to the potatoes so they're nicely covered and can get golden.
Mix them with the salt and pepper and take to a preheated oven at 180C for 30-40min or until they're really golden.
Freeze the octopus for at least 24 hours, ideally 48 so the fibers inside the tentacles break to make it more tender when cooked. If you can't do this then you need to go at the tentacles with a meat softener or a cling film-wrapped rolling pin to avoid contamination. Thaw completely before cooking.
Take water to a rolling boil on high heat.
Submerge first the tips of the tentacles and take it out, then go about halfway and finally just submerge all of it.
Make sure that it's completely under water. You can put a bowl on top to make sure that it stays there. Put a lid on and cook 20min per every kilo that the octopus had.
Take of the water and cut the tentacles off. Discard the rest of the body.
Blend the olives with the olive oil and reserve.
We'll start by making a mayonnaise. You can do it with a whisk or in a blender. Put the egg, Dijon mustard, garlic and salt in a bowl and whisk them together until homogeneous. Alternatively you can blend them together.
Add the vegetable oil little by little while whisking or blending.Stop adding oil when you like the texture and finish with a few drops of lime or lemon juice and the blended olives.
* En el video hice doble receta de la salsa porque a mi camarógrafo Mati le encanta la salsa y le mandé a su casa ????