Celeriac gratin topped with pistachios

Serves 6

250g Greek yoghurt

2 tsp Dijon mustard

1 lemon, juice only

2 garlic cloves, finely chopped

2 tbsp flat-leaf parsley, finely chopped

1 tbsp fresh oregano leaves

150g cheddar, grated

pinch cayenne

sea salt to taste

2 big celeriac, peeled, thinly sliced

Topping

2 tbsp freshly grated parmesan

100g breadcrumbs, homemade

30g pistachios, chopped

30g butter, diced

Combine all the ingredients except the celeriac. Add the celeriac slices. Place celeriac mixture into rectangular dish about 32cm square. Combine the topping ingredients except butter. Scatter over topping. Add butter. Bake at 180C for 30 to 40 minutes until tender and golden.