This recipe introduces a white sauce, made using a roux. It’s a very useful skill to have in your repertoire, and can be used in all sorts of other dishes. This particular recipe uses leeks, but would work equally well with other vegetables and is a great way of using up any roast veg left over from a Sunday roast – just stick them in a baking dish, cover with your white sauce, pop a quick crumble mix on top, and you have another meal!

Serves [2] 4

2-4 leeks, depending on size
[100ml] 200ml boiling water
[20g] 35g butter
[½ tbsp] 1 tbsp flour for the roux
[25g] 50g flour
[25g] 50g oats
[20g] 40g cheddar, grated
[½ tsp] 1 tsp thyme
[5] 10 sage leaves, cut up
[½ tsp] 1 tsp dijon mustard
[2 tsp] 3-4 tsp sesame seeds
salt and pepper

Wash and trim the leeks and cut up into small batons. Cook them in boiling salted water until tender, about 6-8 minutes. Remove the leeks with a slotted spoon and place evenly in a baking dish. Keep [100ml] 200ml of the water to the side, we will use this later.

Put half of the butter into a saucepan and melt over a medium heat. Add a tablespoon of flour and stir quickly. The flour and butter will combine and cook quickly, in about 2 minutes, to make a roux, a thickish doughy mixture. Add the boiled leek water to the roux and whisk quickly, using a whisk, spoon or fork.

Cook the sauce for 8-10 minutes, until the flour is cooked out (there are no lumps) and it has a velvety look to it, like double cream. Add half of the grated cheddar and stir it in until it melts.

Take the sauce off the heat and add the mustard, thyme, sage and taste for salt and pepper. Pour the sauce over the leeks in the baking dish.

Make the crumble topping: In a bowl, mix the flour and oats together and rub in the rest of the butter using your fingertips, until it resembles breadcrumbs. Add the rest of the cheese and the sesame seeds and stir to combine.

Scatter the crumble topping evenly over the leeks and bake in a preheated oven at 180C/gas mark 4 for 35-40 minutes, until bubbling beneath and golden on top.

This recipe is shared as part of the Good Food Club. We are very grateful for funding from The National Lottery Community Fund, distributed by the Landworkers’ Alliance, which has allowed us to offer a pilot of the Good Food Club this year. Thanks to National Lottery players for making this possible.