1 - Heat the olive oil in a non-stick frying pan then add the sliced onion and cook on a medium heat until completely softened, so around 15 mins, adding a little splash of water if they start to stick at all.

2 - Crush in the garlic and cook for a 2-3 mins further, then add the butter.

3 - Once the butter is foaming a little, add the mushrooms and cook for around 5 mins until completely softened.

4 - Season everything well, then tip onto a plate.

5 - Tip the flour into a bowl with a big pinch of salt and pepper, then toss the steak in the seasoned flour.