The problem:

I’m never happy with the dull color green beans turn when I cook them. Am I cooking them wrong?

The solution:

You’re not necessarily cooking them wrong; you’re just cooking them too long. Green beans get their vibrant color from the pigment chlorophyll. But chlorophyll, unfortunately, loses its luster in the presence of acids, and when a green bean cooks, its cells breakdown, allowing natural acids to escape and react with the bean’s chlorophyll. To curtail color loss, simply limit the cooking time. You could toss the beans in a hot sauté pan or wok for a few minutes and serve them crisp-tender. Or if you prefer your beans cooked through, steam or boil for up to five minutes and promptly drain them. If you serve them immediately, their color should still be pretty.

That said, color isn’t everything. Slow-cooked green beans have a depth of flavor that more than makes up for their lack of good looks. If you do go the quick-cooking route, though, just be sure you don’t dull the beans’ brilliance by dressing them too early with an acidic sauce—wait until right before serving.