Bavette Steak Sandwich with Cantal & Caramelised Onions

This is a very serious sandwich situation. Seared bavette, melted Cantal, caramelised onions, peppery arugula, and plenty of dijonnaise, all piled onto toasted ciabatta. It’s rich, a little messy, and exactly what I want from a steak sandwich.

I served mine with bistro-cut fries, a simple vinaigrette-dressed side salad, and extra dijonnaise on the side.

(Serves 1 to 2 people)

Ingredients

For the steak sandwich:

• 1 ciabatta roll

• 130g bavette steak

• 50g Cantal cheese, sliced or grated

• 1 small handful arugula

• 1 tsp olive oil

• Flakey sea salt (to taste)

• Freshly ground black pepper (to taste)

• 1 tbsp butter

• 2 cloves garlic, lightly crushed

• 2–3 sprigs fresh thyme

For the caramelised onions:

• 1 small/medium onion, thinly sliced

• 1 tsp butter

• ½ tsp brown sugar

• 1 tsp Worcestershire sauce

• Pinch of salt

• Black pepper, to taste

For the dijonnaise:

• 2 tbsp mayonnaise

• 2 tsp moutarde à l’ancienne (wholegrain mustard)

• 1 tsp Worcestershire sauce

• Squeeze of lemon juice

• Freshly ground black pepper, to taste

For the side salad (optional):

• 1 handful mixed salad leaves

• 1/2 tsp moutarde à l’ancienne

• 1 tsp apple cider vinegar

• 1 tbsp olive oil

• Salt, to taste

• Freshly ground black pepper, to taste

To serve (optional):

• Bistro-cut fries

• Extra dijonnaise

Directions

1. Start with the onions. Melt the butter in a pan over medium heat and add the sliced onion with a pinch of salt. Cook for 5–7 minutes, stirring occasionally, until softened and starting to colour.

2. Add the brown sugar and Worcestershire sauce and cook for another 5–10 minutes until the onions are deeply golden and glossy. You don't normally need sugar to caramelise onions — they'll get there on their own if you give them enough time. Here, the brown sugar just speeds things up. They won't be as soft and jammy as onions cooked low and slow for an hour or two, but I actually prefer them with a little more texture in this sandwich. If you want to properly caramelise yours, though, you do you.

3. Make the dijonnaise by mixing the mayonnaise, moutarde à l’ancienne, Worcestershire sauce, lemon juice, and plenty of freshly ground black pepper. Taste and adjust with a little more mustard or lemon if needed.

4. Take the bavette out of the fridge around 20–30 minutes before cooking. Pat it very dry and season generously with salt and freshly ground black pepper.

5. Heat a heavy pan over high heat with the olive oil. Once very hot, add the bavette and leave it undisturbed to develop a good crust. For a bavette around 2–2.5cm thick, use these timings as a rough guide:

   • Rare: around 1½–2 minutes per side (50–52°C internal temperature)

   • Medium-rare: around 2–2½ minutes per side (54–57°C)

   • Medium: around 2½–3 minutes per side (60–63°C)

   • Medium-well: around 3–3½ minutes per side (65–67°C)

   • Well-done: around 4 minutes or more per side (70°C+)

   I recommend medium-rare to medium for this sandwich. The exact cooking time will depend on the thickness of your steak and how hot your pan is, so an instant-read thermometer is the most reliable way to check for sure.

6. During the final minute of cooking, lower the heat slightly and add the butter, crushed garlic, and thyme. Once the butter begins to foam, tilt the pan and repeatedly spoon the garlic and thyme-infused butter over the steak to baste it.

7. Transfer the bavette to a board and let it rest for 5–10 minutes before slicing thinly against the grain. This is especially important with bavette and makes it much more tender to eat in the sandwich.

8. Slice the ciabatta in half. Lightly butter the cut sides and toast until golden. Add the Cantal to the top and bottom half and place under the grill until melted and bubbling.

9. Spread a generous amount of dijonnaise over the bottom half of the ciabatta. Add the arugula, followed by the sliced bavette and caramelised onions. Finish with the Cantal-covered top half and press everything together.

10. For the optional side salad, whisk together the moutarde à l’ancienne and the vinegar. Slowly whisk in the olive oil until emulsified, then season with salt and black pepper. Toss with the salad leaves just before serving.

11. Slice the sandwich in half and serve immediately with bistro-cut fries, the side salad, and extra dijonnaise for dipping.

12. Bon Appétit!