1. Fill a large bowl with ice water and set aside.
2. Bring a large saucepan of water to a boil, add the green beans and a few generous pinches of salt, and blanch the green beans until their color brightens, 30 to 60 seconds.
3. Drain the green beans in a colander, then plunge them into the ice water to stop the cooking. Drain again and set aside on a paper towel-lined plate to dry.
4. Place a large skillet over medium heat, add the pine nuts, and toast them, shaking the pan often, until they are lightly browned and fragrant. Transfer the pine nuts to a small plate to cool.
5. Add the butter and oil to the skillet and reduce the heat to medium-low.
6. Once the butter is melted, add the blanched green beans.
7. Season with salt and cook, stirring often, until the green beans begin to brown in spots, 2 to 3 minutes.
8. Add the garlic and cook until fragrant, about 30 seconds (don’t let the garlic brown). Turn off the heat and squeeze the lemon over the beans.
9. Transfer the green beans to a platter and serve sprinkled with toasted pine nuts, cheese, and red pepper flakes (if desired).

Pro Tip
Restaurant chefs love to blanch vegetables in advance, because they can be sautéed quickly before serving. The technique also works well at home, especially for dinner parties, because having parcooked vegetables handy allows you to get them to the table faster, giving you more time with your guests. If you decide to blanch vegetables, don’t skip shocking them in ice water, as it sets the green color and stops them from overcooking. Pat dry with clean towels before sautéing so they take on a nice sear. Blanched vegetables can be refrigerated for up to 2 days before finishing them in a skillet.