8 field mushrooms, peeled and thickly sliced
4 plum tomatoes, halved lengthways, seeds and core removed
300g/10oz cooked mashed potatoes, warm
75g/3oz plain flour
150ml/5fl oz Worcestershire sauce
salt and freshly ground black pepper
pinch ground mace
50ml/2fl oz sunflower oil
75g/3oz butter
4 free-range eggs
1 free-range egg yolk
12 rashers streaky bacon