Pile the flour on the work surface and stir in a pinch of salt. Create a well in the middle and place the butter around the well. Crack the egg into the well and add 2-3 tbsp lukewarm water. Chop all the ingredients up together so that breadcrumbs are formed. Quickly knead into a ball, wrap in cling film and chill for 30 minutes.
Heat the oven to 200°C (180°C in a fan oven), 400°F, gas 6 and grease two quiche tins.
Blanche the broccoli and cauliflower in boiling salt water for 4-5 minutes. Quench and drain.
Mix together the cream, eggs and cheese and season with salt, ground black pepper and nutmeg.
Roll the pastry out onto a lightly floured surface and place in the two prepared tins creating an edge. Place the broccoli and cauliflower on top and pour the egg-cream mixture over them. Sprinkle with the slivered almonds and bake for 35-40 minutes. Remove from the oven and serve immediately.