Asparagus, beetroot and horseradish tart

SERVES 6 BASE 1 x 320g all-butter puff pastry sheet 1 egg yolk 1 tbsp milk ON TOP 2 tbsp good olive oil 1 red onion peeled halved and thinly sliced 150g cooked peeled beetroot (unvinegared) thinly sliced sea salt and black pepper 150g thin asparagus (trimmed weight) halved across if necessary 2 medium egg yolks 2 heaped tsp horseradish sauce 50g crème fraîche 1 tbsp milk

Have ready the unrolled sheet of shop-bought puff pastry. Combine the egg yolk with the milk in a small bowl and set aside. Preheat the oven to 200C/180C fan/gas 6 with a baking sheet inside.

For the topping, heat a tablespoon of oil in a large nonstick frying pan over a medium heat and fry the onion for 5 minutes until softened and lightly coloured, stirring frequently. Stir in the beetroot and season. Toss the asparagus in a large bowl with the remaining oil and a little seasoning. Whisk the egg yolks, horseradish and crème fraîche together in a small bowl, then stir in a tablespoon of milk to achieve a thick drizzling cream.

Unroll the pastry leaving it on its base (it should measure about 23cm x 35cm). Brush a 2cm rim of pastry all the way round with the egg wash.

Spread the onion and beetroot to within about 1cm of the rim, then scatter over the asparagus and drizzle over the horseradish cream. Slip the tart on its paper on to the hot baking sheet and bake for 30 minutes or until the cream is golden and the vegetables are tender and lightly coloured. Serve about 20 minutes out of the oven.