You can bake the pea filling into the tart a couple of hours ahead, then add the veg and quail’s eggs 10 minutes before you’re ready to serve. Just add a minute or two to the second baking time.
Tip the bread mix into a large bowl and add the oil and 175ml lukewarm water. Knead for 5-10 mins until you have a smooth, elastic dough, then cover with cling film and leave to rise until doubled in size.
Whizz the peas and cream cheese together in a blender or food processor until smooth, then stir in the soured cream, egg, shallots and sugar with some seasoning. Bring a medium pan of water to the boil. Add the broad beans for 30 secs, then lift them out with a slotted spoon into a bowl of cold water. Gently squeeze the bright green beans out of their thick skins and discard the skins. Meanwhile, add the leeks to the boiling water for 1 min 30 secs, then add the asparagus and boil for 1 min more. Drain well.
Heat oven to 200C/180C fan/gas 6. Roll the dough out on a large baking sheet to a rectangle 14 x 40cm, pressing down the centre to create a thicker ‘crust’ around the edge. Spread the pea cream in the middle of the tart and bake for 20 mins. Scatter over the leeks, asparagus and broad beans, then carefully crack over the eggs – you can arrange the veg to create little pockets if it helps. Drizzle with rapeseed oil and bake for another 5-7 mins. Scatter a few pea shoots over and serve straightaway, cut into thin slices.