Leek crumble

Preheat the oven to 180°C/gas mark 4

Add the butter to a large frying pan and set over a medium heat. When foaming, add the leeks and fry until almost cooked with a slight colour. Pour into 4 individual oven dishes, or one big ovenproof dish and leave to one side

Melt the butter in a medium-sized saucepan. Add the flour and cook for 5 minutes, stirring to avoid lumps. Whisk in the stock followed by the milk and cook until thick, making sure you stir continuously

Add the cheddar, salt and two mustards and mix to combine. Pour the sauce over the leeks to cover

To make the topping, combine the oats, flour, sesame seeds, thyme and seasoning in a large bowl. Add the butter and rub the mixture together until the it resembles breadcrumbs

Add the cheese and mustard, mix again and sprinkle over the leeks. Place in the oven for 20 minutes until the topping is a nice golden-brown and the filling is bubbling. Serve with tomato chutney and salad