225–250g/8–9oz leftover vegetables, such as kale, spinach, chard, Brussels sprouts, cabbage, leeks
1 small onion, thinly sliced
300g/10½oz leftover cooked potatoes
small handful chopped fresh herbs, such as thyme, rosemary or parsley (optional)
salt and freshly ground black pepper
1 tsp oil, plus extra for frying
25g/1oz butter
2 free-range eggs