Three-Bean Salad with Vinaigrette

Fill a large bowl with ice water; set aside. Set a steamer basket in a large pot with a lid. Fill with enough water to come just below basket; bring to a boil.

Place green and wax beans in basket; reduce heat to a simmer. Cover pot, and steam until beans are crisp-tender, 6 to 8 minutes. With tongs or a slotted spoon, transfer beans to ice water. Drain, and pat dry.

In a medium bowl, whisk together mustard, vinegar, and oil; season with salt and pepper. Add green, wax, and cannellini beans; toss to coat. If storing, cover and refrigerate up to 1 day; bring to room temperature before serving.