Put the octopus into cold water until it is defrosted. Then remove the head from the tentacles. Carefully separate the tentacles from one another with a knife. Add in a deep saucepan water. Put in the wholesale cut vegetables and cover it with a foil. After the water boils and the foil lifts up, create a small hole in the center and drop there the tentacles one by one. If the tentacles are boiled separately boil the octopus for around 40 minutes. In case the whole octopus is boiled then it will take 1hour and 20 minutes. Check whether the octopus is cooked with a wood skewer. If piercing the tentacles in their thickest part is easily done, then the octopus is cooked. If the octopus will not be consumed immediately it is better to cool it down with ice cubes in order to prevent overcooking which will lead to falling of the suction cups. The octopus can be additionally grilled for more flavor.