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Steak Sandwiches with Fennel Slaw

This high-protein steak sandwich is a sophisticated way to transform leftover beef into a vibrant, restaurant-quality lunch. By pairing chilled, thinly sliced steak with the aniseed crunch of fennel and the zingy brightness of coriander salsa verde, you create a balanced dish that feels remarkably fresh. The combination of tender meat and crisp vegetables, tucked into a toasted focaccia, provides a satisfying contrast in textures that is far more elevated than your standard sandwich fare.

Ideal for a quick midweek meal or a nourishing weekend lunch, this recipe is as practical as it is delicious. Using shop-bought or leftover salsa verde ensures it comes together in minutes, while the fennel and red onion slaw adds a boost of fibre and nutrients. Serve this hearty sandwich as it is for a filling, protein-rich meal that makes the absolute most of your fridge staples.

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Ingredients for Steak Sandwiches with Fennel Slaw

  • 1 chilled leftover steak (from Pan-Roasted Steak with Crispy Broccoli)

  • 1 small fennel bulb, very thinly sliced, plus coarsely torn fronds

  • 1/2 small red onion, very thinly sliced, rinsed

  • 1/4 cup leftover coriander salsa verde (from Pan-Roasted Steak with Crispy Broccoli)

  • 1/2 teaspoons kosher salt, plus more

  • Freshly ground black pepper

  • 1 sandwich-size piece focaccia, split lengthwise, toasted

  • 60ml mayonnaise

Slice steak against the grain into as-thin-as-you-can-get-them strips (this is much easier to do when the steak is cold). Transfer to a large bowl and let sit at room temperature while you make the slaw. If you have time, slice the steak before you start cooking; an hour is ideal to completely take off the chill.

Toss sliced fennel, red onion, salsa verde, 1/2 teaspoons salt, and 1 tablespoon fennel fronds in a large bowl to combine. Season slaw with a few grinds of pepper and toss again.

Spread cut sides of focaccia with 2 tablespoons mayonnaise each; transfer to plates. Divide steak between bread and crown each sandwich with a big handful of slaw. (You may have a small amount left—nibble on it or serve on the side.) Top sandwiches with more fennel fronds and sprinkle with salt.

Disclaimer

While every effort has been made to ensure the information is accurate and up to date, individual needs may vary and dietary requirements can differ based on personal health conditions. Always check food labels and allergen information before preparing or consuming any recipe. If you have specific health concerns, allergies, intolerances, or are following a medically prescribed diet, seek advice from your GP, pharmacist, or a registered dietitian before making significant changes to your diet or lifestyle.

Article history

The information on this page is peer reviewed by qualified clinicians.

  • 28 Jan 2026 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
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