Master Recipe 
I have lost count of the number of times I have ordered fried squid in restaurants, only to be served soggy, undercooked seafood. But this surefire method creates golden, crispy squid every time. Turmeric, an Indian spice, is responsible for the bright golden color of the batter and adds a gentle, exotic flavor to the crispy squid. When I can’t find squid in the market, I prepare this with onions for a simple vegetarian variation.
When testing to find the ultimate batter recipe, I found that a beer-based batter consistently gave the best results. I am not a scientist, but modernist cuisine innovator and renowned food scientist Nathan Myhrvold offered compelling reasons for why beer makes the lightest, crispiest, and tastiest batter:
• Beer brings three important components to a batter: carbon dioxide, foaming agents, and alcohol.
• Gas dissolves in liquids at low temperatures, and reacts with it at higher temperatures. So when the carbon dioxide in beer comes into contact with the hot oil, the bubbles actually expand in the batter mix rather than dissolving (as, say, sugar would), resulting in a very light and lacy texture.
• The foaming agents in beer also help to achieve a light and airy result by forming a protective casing around the bubbles that prevents them from popping too fast. They also act as a thermal insulator, heating up to 266°F (130°C; the point at which the Maillard reaction begins to work) and effectively helping to create that perfectly deep golden crust while insulating the delicate food inside from overcooking.
• While it may seem counterintuitive that a food submerged in oil dries as it cooks, that is basically what the crust is doing, as water evaporates from the batter and the food inside. Alcohol evaporates faster than water, so a beer batter does not have to cook as long as a batter prepared with water or milk, and the faster the batter dries, the less risk of overcooking the food it is surrounding.
• Why cornstarch? Cornstarch, which is 100 percent starch and finely textured, seals the ingredients it coats, helping to promote crisp-textured fried foods. It also helps to prevent gluten from developing in the flour, too much of which can make batters puffy and heavy.
6 APPETIZER SERVINGS
EQUIPMENT: A 3-quart (3 l) heavy-duty saucepan or cast-iron pot or a deep-fat fryer fitted with a basket; a deep-fry thermometer or a wooden chopstick (optional); a frying screen (optional); a wire skimmer; a tray lined with paper towels.
1 pound (500 g) small squid (2 to 3 inches/5 to 7 cm long)
5 tablespoons (50 g) unbleached, all-purpose flour
5 tablespoons (50 g) cornstarch
1/2 teaspoon fine sea salt, plus more for seasoning
1 teaspoon ground turmeric
2/3 cup (160 ml) beer
1 quart (1 l) vegetable oil, such as sunflower oil
A selection of sauces, such as Aïoli Piquant or Chile-Lime Aïoli, Lime Mayonnaise, Harissa Yogurt Sauce, and infused salts (favorites for this dish are Piment d’Espelette Salt, and Saffron Salt), for serving
1. Rinse the squid and cut the bodies into 1-inch (2.5 cm) rings; halve the tentacles.
2. In a large bowl, combine the flour, cornstarch, salt, and turmeric. Set aside 1 tablespoon of the mixture to dust the squid later on. Add the beer to the dry ingredients in the bowl and whisk until the batter is smooth and lump-free.
3. Pour the oil into the saucepan or deep-fat fryer to a depth of at least 2 inches (5 cm). Heat the oil over medium heat to 375°F (190°C), or until a wooden chopstick inserted into the oil begins to fizz with bubbles. Do not be tempted to use too high a heat to bring the oil to temperature, as it will be harder to control and keep stable once you arrive at your goal temperature.
4. Dry the squid with paper towels. Dust the squid with the reserved flour mixture. Working in five or six batches, add the squid to the batter. Drag each piece against the side of the bowl to remove any excess batter, and drop gently into the hot oil, one at a time. Wait a few seconds before adding each piece, to prevent them from sticking together. Should they stick to the wire basket if using a fryer, dislodge them with the chopstick. If necessary, use a frying screen to keep the oil from spattering. Fry each piece until golden, about 2 minutes. Using the wire skimmer, transfer the squid to the paper-towel-lined tray to drain. Repeat with the rest of the squid. Season lightly with salt. Serve immediately, with a choice of sauces and salts.
VARIATION
Use 1 large onion in place of the squid, sliced crosswise into thin rings, then follow the remaining steps as above.
MAKE-AHEAD NOTE: In our tests we found that the batter can easily be made a day in advance and stored in an airtight container in the refrigerator. Whisk again before using to coat the squid.
BEVERAGE MATCH: Try this with a favorite chilled local artisanal beer.