In this recipe, I blanch the broccoli before sautéing it. I love vegetables sautéed in olive oil that’s fragrant with garlic, but too often, these sautés can turn fresh, crisp produce into something greasy and soggy. So for some thicker-cut vegetables like broccoli florets, the blanching step really helps: By boiling, you cook the veggies most of the way through, and then you finish with the sauté more for flavor and texture than to get the broccoli fully cooked. Less time in the oil, less chance of sogginess.
Bring a Large Pot of salted water to a boil. Add the broccoli and cook just until the color brightens, about 2 minutes. Using a slotted spoon, transfer the broccoli to a large bowl of ice water to cool completely. Drain the broccoli and set aside.
Cook the green beans in the same pot of boiling salted water just until the color brightens, about 4 minutes. Drain, then add the green beans to another large bowl of ice water to cool completely. (The vegetables can be prepared up to this point 8 hours ahead. Dry thoroughly and refrigerate in a resealable plastic bag.)
In a large sauté pan, heat the oil over a medium-high flame. When almost smoking, add the garlic and 1½ teaspoons of red pepper flakes, and sauté just until fragrant and the garlic is pale golden, about 45 seconds. Using a slotted spoon, remove the garlic from the oil and discard (do not overcook the garlic as it will impart a very bitter taste to the dish). Add the broccoli, green beans, and ½ teaspoon each of sea salt and black pepper to the oil, and sauté until the vegetables are heated through and crisp-tender, about 5 minutes. Season with more red pepper flakes, sea salt, and black pepper to taste. Transfer the mixture to a bowl and serve immediately.