Steak Sandwich with Caramelised Onions

• 2sirloin steaks, about 200 g each (400 g total)
• 2onions, thinly sliced
• 20 gbutter
• 1 tbspolive oil
• 1 tspbalsamic vinegar
• 1 tspsoft brown sugar
• 4ciabatta rolls, about 80 g each, split
• 2 tbspDijon mustard
• 2 tbspmayonnaise
• 40 grocket
• Fine salt, to taste
• Black pepper, to taste

Method

1. 1Melt the butter with half the olive oil in a heavy frying pan over medium-low heat. Add the onions with a good pinch of salt; salt now pulls the water out and speeds the jamming. Cook slowly for 30–40 minutes, stirring often, until deep mahogany and sticky at the edges. Rush this and you get sweaty onions; take your time and you get jam.
2. 2Stir in the balsamic vinegar and brown sugar for the last 2 minutes; the splash of vinegar cuts the sweetness and lifts the whole pan. Tip the onions into a bowl and wipe the pan clean for the steaks.
3. 3While the onions go, pat the steaks bone-dry with kitchen paper. Rub all over with the remaining olive oil and season generously with salt and plenty of black pepper. Leave them on the board to come up to room temperature.
4. 4Set the same pan back over a high heat until very hot, without letting it smoke heavily. Lay the steaks in well apart; don't crowd the pan, or the heat drops and they'll stew instead of sear. Cook 2–3 minutes per side for medium-rare, pressing for full contact. Pull at 52°C internal; the temperature carries up to 55°C as they rest. Lift onto a board and rest for 5 minutes; this is important, or the juices end up on the board instead of in the meat.
5. 5Stir the Dijon and mayonnaise together in a small bowl until smooth. Taste it; it should be sharp enough to wake the steak up; adjust with a pinch of salt if it needs lifting.
6. 6Toast the ciabatta halves cut-side down in the still-hot pan for 1–2 minutes until golden and crisp; the residual beef fat seasons the bread on the way through.
7. 7Slice the rested steak across the grain into thick strips, spooning any board juices back over them.
8. 8Spread the mustard mayo generously on both cut sides of the ciabatta. Divide the filling between the four rolls. Pile in the rocket, heap the caramelised onions on top, layer over the sliced steak with its juices, and press the lids down gently.

Per serving

kcal

541

protein

35g

fibre

4.7g

carbs

53.2g

fat

22.2g