Thinly slice steak into eight pieces. Set aside. Heat oil in a pan and cook onion until softened. Lower heat and continue to cook for about 10 minutes, until onion starts to colour and get crunchy around the edges.

Brush sourdough with a little oil and cook on a hot grill plate for a few minutes either side, or toast the bread. Wilt spinach for a few minutes in a small non-stick pan. Cook steak in a very hot pan with a little oil for about 30 seconds either side. Season with salt and pepper and set aside, keeping warm.

Pile wilted spinach on a slice of toast, top with two slices of steak and lashings of onions. Dollop with good-quality chutney and top with a second slice of toast.