Open Beef Sandwich with Caramelised Onion, Béarnaise Sauce and Salad

Steps

1. oven to 180°C. Line an oven tray with baking paper.
2. Heat a drizzle of olive oil in a medium pot on medium heat. Fry onion for 5 minutes until soft and starting to colour. Add balsamic vinegar and sugar, reduce heat to low and simmer gently for 10 minutes until thickened and glossy, stirring often to avoid burning.
3. Heat a drizzle of olive oil in a large fry-pan (preferably non-stick) on medium to high heat. Pat beef dry with paper towels and season with salt and pepper. Fry for 3–4 minutes each side until brown. Transfer to prepared tray and bake for about 6 minutes for medium-rare (depending on thickness) or until cooked to your liking. Transfer to a plate to rest for 5 minutes before slicing thinly against the grain.
4. While beef is cooking, place sourdough directly on oven rack and bake for 6 minutes. Remove from oven, allow to cool slightly then cut into 1.5cm thick slices.
5. While steak is resting, prepare salad; separate cos lettuce leaves; slice tomatoes and cucumber. Place all on a serving platter.
6. Top a piece of sourdough with some salad, sliced beef caramelised onions and béarnaise sauce. Top with another slice of sourdough if desired.