- new potatoes 300g
- asparagus 400g, trimmed and cut into 3-4 pieces
- butter 80g, plus extra for the tin
- onion 1, finely chopped
- plain flour 80g
- whole milk 800ml
- spinach 75g
- nutmeg a good grating
- Dijon mustard 1 tsp
- Italian hard cheese 100g, finely grated
- frozen peas 75g
- eggs 5 large
- red onions 2, thinly sliced
- red wine vinegar 2 tbsp
- flat-leaf parsley a small bunch, leaves picked
Heat the oven to 180C/fan 160C/gas 4 and butter and line a deep 23cm springform cake tin.
Cook the potatoes in a large pan of lightly salted boiling water for 8-10 minutes or until tender to the point of a knife. Scoop out with a slotted spoon, then add the asparagus for 2 minutes and drain well. Cut the potatoes into 1-2cm slices.
Heat the butter with the onion and a pinch of salt and cook for 5 minutes until softened. Add the flour and cook for 2-3 minutes until smelling toasty. Add the milk, a little at a time, while whisking, adding more once fully incorporated.
Simmer for 5 minutes until thickened, then stir in the spinach, nutmeg, mustard, Italian hard cheese, and lots of seasoning. Cool for 5 minutes, then stir in the asparagus, new potatoes, and peas. Crack in the eggs and whisk well, then pour into the prepared tin and put into the oven for 45-50 minutes or until cooked through.
Put the onions into a bowl with a pinch of salt and the vinegar and use your hands to scrunch them until they soften slightly.
Cool the sformato for 10 minutes in the tin, then remove the sides, invert onto a plate and cool to room temperature. Stir the parsley into the onions, drain, scatter over the top of the sformato, cut into wedges and serve.