- 1 1/2 pounds broccoli – cut into florets, stems peeled and sliced 1/4 inch thick
- 2 tablespoons white wine vinegar
- 2 teaspoons Dijon mustard
- 1/2 teaspoon prepared horseradish, or to taste
- 3/4 teaspoon salt
- 1/8 teaspoon ground black pepper
- 1/2 cup olive oil
- 3 tablespoons sour cream
- 3/4 pound thick sliced deli roast beef, cut into 1/2-inch pieces
- 2 1/2 cups cherry tomatoes, halved
- 6 green onions cut diagonally into thin slices
- Pour 1/2 inch of water into a pan fitted with a steamer basket. Place the broccoli in the basket. Cover, and bring to a boil. Cook until tender, about 4 to 5 minutes. Drain, and cool.
- To make the dressing, whisk together the vinegar, mustard, horseradish, salt, and pepper in a bowl. Continue whisking while slowly adding the olive oil to make a smooth mixture. Whisk in the sour cream.
- Place the broccoli, roast beef, tomatoes, and green onions into a bowl. Stir in the dressing and toss until evenly coated. Divide the salad evenly among 4 serving plates.