INGREDIENTS     500g (1lb 2oz) strong plain flour, plus extra for dusting     2tsp salt     1 x 7g sachet of dried yeast     320ml (11fl oz) lukewarm water     A few dried breadcrumbs or a bit of semolina, for dusting FOR THE TOPPING     80g (3oz) Gruyère cheese, grated     250g (9oz) crème fraîche     Salt and freshly ground black pepper     1 large red onion, thinly sliced     140g (5oz) salami, cut into strips     A few marjoram leaves METHOD Preheat the oven to 240°C/fan 220°C/ gas 8. Combine the flour, salt and yeast in a large bowl. Gradually add the water, mixing well with your hands to make a dough. If you find the dough too sticky add a little more flour. Shape into a ball, cover with a cloth and leave to rest for 5 minutes. Knead the dough for about 10 minutes and split it in half. Sprinkle some flour on a clean kitchen cloth and place the pieces of dough on it. Cover with a slightly damp cloth and leave to rise for at least 30 minutes in a warm place. Meanwhile combine the Gruyère and crème fraîche in a bowl, adding some salt and pepper to taste. Set aside. Sprinkle some flour on a clean work surface and spread the dough into a circle about 30cm (12in) in diameter, making it as thin as possible (without tearing it), with the border slightly thicker. Repeat with the other dough ball. Sprinkle two baking trays with breadcrumbs or semolina and place the bases on them. Spread the crème fraîche mixture over each base. Top with the onions and salami. Bake in the hot oven for 10 minutes. Remove, sprinkle with the marjoram and serve.