First clean the octopus, put it in a large pot, cover it with plenty of water, bring to a boil and cook for about 30 minutes.
Once cooked, drain, let it cool and cut into pieces.
In the meantime that the octopus is cooking, peel the potatoes, cut them into cubes, then cook them with a little water in a large saucepan where you have dried the mixture for sautéed with oil.
When the potatoes are cooked, season them with plenty of pepper and pecorino and blend with the blender until you get a smooth cream without lumps.
Meanwhile, brown the diced octopus in a non-stick pan with plenty of oil.
When the octopus and potatoes are almost ready, add the pasta to cook in a pot with plenty of boiling salted water.
Drain it a little al dente keeping a little of the cooking water, then add it to the potato cream (adding a little cooking water if needed), season with salt, finally add the octopus too, keeping a few pieces aside for decorate the dishes.
The pasta with cream of potatoes and octopus is ready: serve, decorate with the octopus set aside and a little fresh parsley and serve immediately.