Name: Leek gratin with crispy leek topping
Prep time: 30 min
Cook time: 1 h
Total time: 1 h 30 min
Yield: 4-6 as a side
Ingredients: 400g leeks , trimmed and washed; 3 tbsp olive oil; 2 tbsp plain flour; 2 tbsp butter; 400ml milk; 1 tsp English mustard powder; 2 bay leaves; 140g mature cheddar , grated; 25g panko breadcrumbs; 2 tsp thyme leaves; ½ lemon , zested

A leek gratin in a green dish with a Christmas cracker in the background

400g leeks
trimmed and washed
3 tbsp olive oil
2 tbsp plain flour
2 tbsp butter
400ml milk
1 tsp English mustard powder
2 bay leaves
140g mature cheddar
grated
25g panko breadcrumbs
2 tsp thyme leaves
½ lemon
zested

Method

step 1
Cut most of the leeks into 3cm pieces, finely slicing 10cm of the white part of one leek for the topping.
step 2
Steam the bite-sized pieces for 6-8 mins, or until just tender, then leave to steam-dry. Meanwhile, heat the oil in a frying pan over a medium heat and fry the finely sliced leek for 15-18 mins, stirring regularly until crisp and golden. Scoop onto kitchen paper to drain, and season with salt. Keep the oil in the pan to one side, off the heat.
step 3
Heat the oven to 200C/180C fan/gas 6. Warm the flour and butter in a pan until they form a thick brown paste, then gradually add the milk, a splash at a time, stirring until a smooth sauce forms. Stir in the mustard, bay leaves and most of the cheddar. Season with salt and pepper.
step 4
Stir the steamed leeks into the sauce and transfer to an ovenproof dish. Scatter over the remaining cheese and bake for 35-40 mins until bubbling and golden on top.
step 5
Reheat the reserved oil over a medium heat and fry the breadcrumbs for 4-5 mins, or until golden brown and crisp. Drain on kitchen paper. Stir together the crispy leeks, breadcrumbs, thyme leaves and zest in a bowl with some seasoning. Once the gratin comes out of the oven, scatter over the crispy leek and breadcrumb topping.