In a large skillet, heat the butter over medium-high heat.
2 tablespoons unsalted butter
When the butter starts foaming, add the green beans and salt.
1 pound fresh green beans, ½ teaspoon sea salt
Cook, stirring often, for about 5 minutes.
Add the black pepper, garlic, and red pepper flakes.
½ teaspoon black pepper, 1 tablespoon fresh garlic, ¼ teaspoon red pepper flakes
Continue to cook, stirring often, for about 5 more minutes, until the beans are tender but not mushy. Serve immediately.
Video
Notes
Seasonings, especially salt, are guidelines. Adjust to taste.
The most important thing is to avoid overcooking the beans. You want them tender, but they should still have a bite, much like "al dente" when cooking spaghetti. You definitely don't want them mushy or droopy.
Whether you cut the beans in half or leave them whole is up to you. Both work.
You can keep the leftovers in an airtight container in the fridge for 3-4 days. Reheat them gently in the microwave at 50% power. They are also good when served cold, antipasti-style. Sometimes, I chop them up and add them cold to a salad.