Octopus is somewhat of a foreign sea beast to some people. When cooked the right way, the octopus skin will be firm and a little chewy with tender meat inside, but it’s a little trickier to cook than most seafood. The tentacles, which are muscles, will contract and turn rubbery if you cook them too quickly, so don’t ever let the water boil vigorously.
You can also use a pressure cooker, which I tried for the first time while competing on a television cook-off show (we all learn new things when we are under kitchen pressure—literally). Ten minutes in a pressure cooker, followed by a 20 minute rest in the cooking water (with the pressure cooker still locked), and I had some of the best octopus I’d ever eaten. Fortunately, the judges liked it, too. I also always use the simple tenderizing techniques I learned from Japanese sushi chefs when I was in London. Most of the octopus you find today is sold frozen, usually only the tentacles, which are all you need. You can boil and slice the octopus up to a day before you plan to serve it.
To prepare octopus: Preheat the oven to 350°F. If using frozen tentacles, thaw them completely. Cut the tentacles into two or three sections if they are large. Fill a medium saucepan halfway with water, bring the water to a boil, then reduce the heat to maintain a simmer and add the octopus and 1 tablespoon salt. Simmer the octopus (don’t let the water boil) until tender, 30 to 45 minutes, depending on the thickness of the tentacles. To test, prick the octopus with a knife. The skin will be firm, but when you cut through it, the middle of the tentacle should be much softer. Don’t overcook the octopus or it will become rubbery. Drain, transfer the octopus to a baking sheet, and put it in the oven for 5 minutes to dry out completely. Remove the octopus from the oven and let cool completely.
Slice the tentacles at an angle, as when slicing other raw fish, only very subtly move your knife back and forth like the waves of the ocean as you slice. This will help tenderize the meat. To tenderize each slice further, make small, crosshatch slashes with a sharp knife on both sides of each piece. Don’t go very deep—you just want to lightly score the surface of the flesh.