Rinse the octopus under cold water
Remove the beak, eyes, and innards if not already cleaned
Tenderize by freezing overnight or by gently pounding
Bring a large pot of water to a boil
Add aromatics if desired, such as bay leaves, peppercorns, onion, or garlic
Dip the octopus in and out of the boiling water a few times to curl the tentacles
Lower the octopus into the pot
Reduce to a gentle simmer
Cook until tender, usually 30 to 90 minutes depending on size
Test doneness by piercing the thickest part with a knife or skewer
Remove the octopus from the water
Let it cool slightly
Cut into serving pieces
Grill, sear, roast, or serve as desired
Season with salt, olive oil, lemon, and herbs before serving