Melt butter in a large skillet over medium-high heat. Add the green beans and sauté 4–5 minutes until crisp-tender, stirring often.
Whisk together the mustard and red wine vinegar in a small bowl. Continue whisking as you slowly pour in the olive oil. Season with salt and pepper to taste.
Drizzle the mustard dressing over the cooked green beans and toss to evenly coat.
Transfer the salad to a serving bowl and sprinkle with sliced almonds. Enjoy!
Notes
We tossed our green bean salad with sliced almonds but feel free to use your nut of choice!