Mix the flour and salt in a bowl. Add the yeast, water and oil, mix with a risotto spoon. Knead to form a soft, smooth dough. Cover and leave to rise at room temperature for approx. 1 hr. until doubled in size.
Flatten the dough a little, roll out the dough (approx. 30 x 40 cm) on a lightly floured surface, place on a baking tray lined with baking paper. Spread crème fraîche over the base, leaving a border of approx. 1.5 cm all the way around. Top with the onions, courgette and gorgonzola, season.
Approx. 20 mins. on the bottom shelf of an oven preheated to 240°C. Remove, scatter the rocket on top.