For the Mushrooms: get a large frying pan on to heat and, once nice and hot add the olive oil. Tip in your sliced mushrooms, stir to coat them in the oil, season with salt and pepper and cook for 3 minutes without touching them. This will give them a chance to get nice and golden. Stir and leave them for another 3 minutes. They should have taken on a lovely golden, caramelised colour so now we can add the flavour. Add the butter and garlic. Keep stirring and allow the garlic to cook out for a few minutes. Turn off the heat. Add the chopped parsley and lemon juice. TASTE. Adjust the seasoning as you see fit.