Snap or trim the stem ends, rinse the beans under cold water, and pat them completely dry with paper towels.
Heat a large skillet over medium-high heat. Add the butter and let it melt until foaming. The foam is your signal that the pan is hot enough.
Stir in the garlic and cook for 30 seconds, just until fragrant and pale gold. Do not let it brown.
Add the green beans, sprinkle over the salt and pepper, and saute for 6 to 8 minutes, tossing often, until bright green with lightly blistered spots and a tender-crisp bite.
Take the pan off the heat, stir through the lemon zest, and serve immediately.
