Cut the octopus into 5-6 cm (2-2⅓-inch) large pieces. Cut the thinner part of the legs into a bit longer pieces about 10 cm (4-inch). Discard the eyes and teeth of the octopus and slice open the head. Cut it into 5-6 cm (2-2⅓-inch) pieces as well.
Rinse. Place the octopus in a strainer and rinse well for a few seconds.
Add the octopus to a medium-sized cooking pot.
Add the onions, bay leaf, wine, and 600 ml water to the pot as well.
Bring to a boil and then drop the heat to medium. Partly cover the pot.
Simmer for about an hour until the octopus is tender when pricked with a knife.
Add the tomato paste, pepper, olive oil, and potatoes, and drop the heat to medium-low.
Simmer until potatoes are cooked and the sauce is thickened. It takes about 30-40 minutes. Make sure to shake the pot often and stir and scrape the bottom of the pot every now and then at this point, so the food won't stick at the bottom.
Rest. Let the food sit in the pot for 20 minutes before serving.
Serve with plenty of freshly ground pepper on top!