Grilled Sous Vide Flank Steak with Mushroom Lemon Tapenade

A marinating flank steak doesn’t even need to be marinated ahead when you cook sous vide; it becomes juicy and tender as it cooks in its own juices. Sous vide cooking takes the guesswork out of cooking steak to your desired doneness–the temperature you set your water bath is the internal temperature your steak will cook to, every time! Be sure to sear on a hot grill or grill pan for the final browning. The savoury tapenade with mushrooms is a twist on the French classic and tailor made to go with beef. Roast potatoes or frites and a leafy, vinaigrette-dressed salad would be ideal to complete the meal.
Yield 6 Servings Prep. Time 15 min Cooking Time 255 min Total Time 270 min


Here are the following ingredients:

  • Steak
  • Salt
  • 1 tbsp (15 mL) fresh lemon juice
  • 1½ lb (750 g) Beef Flank Marinating Steak
  • Fresh ground pepper
  • Mushroom Lemon Tapenade
  • 2 tbsp (30 mL) olive oil, divided (approx)
  • 8 oz (250 g) cremini mushrooms, chopped
  • 1 clove garlic, chopped
  • ¼ tsp (1 mL) fennel seeds, crushed
  • Pinch dried thyme leaves
  • ½ cup (125 mL) drained pitted green olives
  • 1 tsp (5 mL) grated lemon zest
  • 1 tbsp (15 mL) freshly squeezed lemon juice
  • Salt and fresh ground pepper
  • 1 tbsp (15 mL) chopped fresh parsley

Shopping List

Here are the following shopping items to buy:


Follow these cooking methods/directions:

  1. Steak: Set up water bath for sous vide and preheat to 130°F (54.5°C) for medium-rare or 140°F (60°C) for medium according to manufacturer’s directions.

  2. Combine fennel seeds and ¼ tsp (1 mL) salt in a small bowl. Pat steak dry with paper towel and pierce all over with a fork. Rub fennel mixture all over steak. Place in a large bag for sous vide (vacuum, sealable freezer or reusable silicone). Pour in lemon juice, massaging to evenly coat meat. Remove as much air as possible and vacuum or manually seal.

  3. Immerse bag in preheated water bath and secure it to the side of the pot with a clip, keeping the top of the bag above the surface of the water. Weigh bag down with a large spoon, if necessary to keep it immersed. Cook sous vide for 4 hours.

  4. Mushroom Lemon Tapenade : Meanwhile, heat 1 tbsp (15 mL) oil over medium-high heat in a large skillet. Cook mushrooms, garlic, fennel seeds and thyme, stirring, for about 10 minutes or until mushrooms release their liquid and start to brown. Let cool slightly.

  5. Combine mushroom mixture, olives, lemon zest and juice in a small food processor until fine or mash in a mortar with pestle. Add just enough of the remaining oil until tapenade is the desired texture. Transfer to a bowl, stir in parsley and season to taste with salt and pepper. Cover and refrigerate for at least 1 hour for flavours to blend or for up to 3 days. Let warm to room temperature before serving.

  6. To serve, preheat barbecue to medium-high (400°F/200°C) or heat a large grill pan over medium-high heat until very hot.

  7. Remove the beef from the water bath. Remove steak from bag, discarding liquid from bag, and transfer to a plate. Pat steak dry with paper towel; season all over with salt and pepper. Lightly oil pan, if using. Grill steak for 2 to 4 minutes, turning once, or until sizzling and well-browned on both sides. Transfer to a cutting board.

  8. Cut steak across the grain on a diagonal into thin slices and serve on warmed plates with Mushroom Lemon Tapenade.