Potato, celeriac and red pepper bake

1.In a small saucepan, gently melt butter, remove from heat and stir in flour, then blend in &1/3; of the milk. Slowly blend in the rest of the milk. Set pan over medium heat and whisk until bubbling. Cook 1 minute, stirring, then remove pan from heat and whisk in ½ a teaspoon of salt, a good grating of nutmeg, white pepper to taste and grated cheddar. Cover sauce with a lid and leave to cool.

2.Cut potatoes in half if they are large, then steam them in their skins, or gently boil, until just tender. Cool, peel and slice.

3.Have ready a large bowl &3/4; filled with cold water to which you have added the juice of ½ lemon. Peel celeriac with a sharp knife, cutting off all the roots. Cut into quarters then into thin slices, dropping it into the water as you go. When all celeriac is done, drain and transfer to a saucepan, cover with cold water and squeeze in the juice from the other half lemon. Bring to the boil, then cook about 15 minutes, until just tender. Drain.

4.In a frying pan, heat oil over medium; cook red pepper and onion. Once the vegetables are sizzling, lower heat and cook gently 15 minutes, until tender and just starting to colour. Season with a little salt and black pepper.

5.Preheat oven to 190°C (fan-forced). Assemble vegetable bake in an ovenproof dish 23cm in diameter and 6cm deep, or similar. Put in potatoes, sprinkling generously with salt, then celeriac. Spoon over tomato passata, then add pepper and onion. Beat egg into cheese sauce and spoon on top of vegetables. Bake 30 minutes, or until puffed and golden.