2. In a large skillet or wok, heat 2 tablespoons of the oil over high heat. Add half of the garlic and stir for 1 minute. Add half of the kale and stir-fry for 3 to 4 minutes, until it turns bright green. Transfer to a large bowl and repeat with the rest of the oil, garlic, and kale. Taste the kale; if it doesn't seem tender enough, replace all the kale in the skillet, add 3 to 4 tablespoons water, cover, and steam for a few minutes. (The kale can be prepared ahead and reheated right before serving.)
Chef Thomas Keller, author of Ad Hoc at Home, explains how to season food with salt and vinegar, and why you should temper your food.