Step 1Fill a large pot with plenty of water (at least 6 quarts) and bring it to a boil. Add enough salt for it to taste like seawater.
Step 2Drop in the green beans and cook them until just blanched (tender-crisp), about 4 to 5 minutes.
Step 3Drain the beans and shock them in ice water. Drain again, pat them dry in a towel, and set aside until ready to use. (If overnight, refrigerate.)
Step 4Just before serving, melt the butter in a large skillet. Add the beans and warm through over medium heat. If they're still too crunchy, you can continue warming them, stirring now and then, until they're the texture you like.
Step 5Remove from the heat and stir in the lemon zest and juice. Add fleur de sel or Maldon sea salt and freshly ground pepper to taste, and serve.
Meyer lemon-toasted almond green beans: Stir in one-fourth cup toasted sliced almonds, then scatter a few toasted sliced almonds on top.
Shallot green beans: Warm the beans in 1 tablespoon extra virgin olive oil instead of butter. Instead of lemon zest and juice, stir in 1 tablespoon sherry vinegar, 2 teaspoons of your highest-quality olive oil and one-fourth cup thinly sliced shallots.
Shallot-red pepper green beans: Warm the beans in 1 tablespoon extra virgin olive oil instead of the butter. Instead of lemon zest and juice, stir in one-fourth cup diced roasted red (or red and yellow) bell pepper and one-fourth cup thinly sliced shallots.
Haricots verts: Substitute whole, trimmed haricots verts for the cut green beans in the original recipe or any of the green bean variations.
Broccoli with Meyer lemon: Substitute broccoli florets for the green beans, cooking about 3 minutes.
Shallot-red pepper broccoli: As above for shallot-red pepper green beans, substituting broccoli florets for the green beans, cooking about 3 minutes.
Brussels sprouts with roasted red pepper: Trim a pound of Brussels sprouts and cut lengthwise into quarters; use those instead of the green beans and cook about 5 minutes. Omit the Meyer lemon zest and juice and stir in 3 tablespoons diced roasted red (or red and yellow) pepper.
Brussels sprouts with hazelnuts: Trim a pound of Brussels sprouts and cut lengthwise into quarters; use instead of the green beans and cook about 5 minutes. Warm in 1 tablespoon canola oil instead of the butter. Instead of the Meyer lemon zest and juice, stir in three-fourths cup chopped toasted hazelnuts and 1 1/2 tablespoons roasted hazelnut oil.