Step 1

Make the dressing: Whisk together the horseradish, olive oil, vinegar and lime zest and juice with a pinch of salt in a large bowl. Taste for seasoning.

Step 2

Cook the green beans: Fill a medium saucepot with water and bring to a boil. Fill a large bowl halfway with ice cubes and add some cold water. Place a colander squarely inside the bowl to make an ice bath. (The colander will keep you from having to pick the beans out from among the ice cubes.) Add salt to the boiling water until it tastes like seawater. Plunge the beans into the boiling water and cook until crisp-tender, 1 to 2 minutes. With a slotted spoon, remove the green beans from the water and transfer to the colander inside the ice bath. Move them around gently so the ice water penetrates the beans and accelerates the cooling process. When fully cooled, drain and arrange in a single layer on a kitchen towel to drain any excess moisture.

Step 3

Make the salad: If the green beans are long, cut in half. Toss the green beans in the dressing and toss to coat. Season with salt and pepper. Refrigerate 30 minutes, then stir to coat with the dressing again and marinate at least another 30 minutes and up to 6 hours. Stir in the basil leaves and serve.