flank steak on a cutting board with a bowl of pasta salad

Flank Steak with Slow-Roasted Tomato Pasta Salad

Last Updated on August 26, 2022

The ingredients for this pasta salad are easy to prep ahead, and flank steak cooks quickly in a grill pan.  Chives, mustard and tangy champagne vinegar bring gourmet flavor to a meal that’s simple to make at home.


Mustard Chive Flank with Slow-Roasted Tomato Pasta Salad

4.58 from 7 votes
Print Pin
Protein: Beef
Cut: Flank Steak, Flat Iron
Diet: Dairy Free, Gluten Free
Course: Main Course, Meal Prep
Prep Time: 1 hour 15 minutes
Cook Time: 1 hour 20 minutes
Total Time: 2 hours 35 minutes
Servings: 4 people


  • 1 pkg ButcherBox Flank Steak or Flat Iron


  • 2 Tbsp grainy mustard
  • 2 Tbsp chives minced
  • 1 Tbsp olive oil


  • ¼ c champagne vinegar
  • 1 Tbsp chives minced
  • ½ tsp kosher salt
  • ¼ tsp freshly ground black pepper
  • 1 tsp grainy mustard
  • ¾ c avocado oil

Oven Roasted Tomatoes

  • 12 oz pkg grape tomatoes halved
  • 2 tsp thyme finely chopped
  • 2 cloves garlic minced
  • 1 Tbsp olive oil
  • ½ tsp kosher salt
  • tsp ground black pepper

Pasta Salad

  • 1 box cooked gluten-free penne pasta
  • 2 ea avocados medium dice
  • 2 c greens (spinach, arugula or spring mix)


  • Mix marinade ingredients together. Rub on flank steak, and let the flank rest at room temperature for 1 hour.
  • Preheat a grill pan over medium heat. Place flank steak on hot pan. Grill for 10 minutes per side, or until a meat thermometer inserted into the thickest part of the flank reads 125°F. Let flank steak rest for 10 minutes before slicing thinly against the grain.
  • Preheat oven to 325°F
  • Mix all ingredients for the tomatoes together. Put tomatoes flesh-side down on wire rack laid on top of baking sheet. Slow roast for 1 hour. Cool to room temperature.
  • Combine vinegar, chives, salt, pepper and mustard in a food processor. Pulse until mixed.
  • On low speed, add avocado oil in a slow, steady drizzle.
  • Toss all salad ingredients including oven roasted tomatoes in salad bowl with vinaigrette. Serve with flank steak and enjoy!
Share on Pinterest!Pin at @Butcher_Box!

Emilie Abijanac is a graduate of New England Culinary Institute with over 20 years of catering experience in Boston. Emilie was the Sous Chef for East Meets West Catering and has worked with Kate’s Table and La Fête. Emilie was also the culinary director of ButcherBox.