Do I have to blanch the green beans?
No, but it is the easiest way to guarantee bright color and crisp-tender texture. If you skip it, sauté a bit longer and add a splash of water, then cover for 2 to 3 minutes to steam them through.
How long should I blanch them?
It depends on thickness. Aim for 2 to 4 minutes. Very thin haricots verts can be done closer to 2 minutes, thicker beans may need 4. Best rule: taste one. It should be bright green with a firm bite, not fully soft.
Can I use frozen green beans?
Yes. Skip blanching. Start by steaming them so they heat through without scorching: add frozen beans to a skillet with 2 to 3 tablespoons water, cover, and cook over medium-high for 4 to 6 minutes until hot. Uncover, let any water cook off, then add butter and olive oil. Add garlic for the last 20 to 30 seconds, then finish with lemon, salt, and pepper.
How do I keep green beans from getting mushy?
Do not overcook the blanch. Start checking at 2 minutes, and stop when they are crisp-tender. Shock in ice water, then dry well. Also, keep the sauté short and hot so they pick up flavor without collapsing. Do not crowd the skillet.
What if I do not have lemon?
Use 1 to 2 teaspoons of apple cider vinegar or white wine vinegar at the end. You want that little hit of acidity to wake everything up.
Can I make these ahead for a holiday?
Yes. Blanch and ice bath the beans up to 24 hours ahead. Dry well and refrigerate. Right before serving, do the quick garlic-butter sauté and finish with lemon.