Cut the tomatoes into quarters, sprinkle them with salt and leave the water to sweat out. Slice the peppers into strips.
Preheat the oven to 210C.
Slice the onions and fry them for 5 minutes in 2 tablespoons of olive oil.
Add the washed spinach.
Drain and season.
Roll out the dough into a rectangle and spread a thin layer of mustard.
Spread the tomatoes, peppers, spinach, onions and crumbled goat's cheese, then drizzle on a spoonful of olive oil and scatter the oregano.
Put in the oven for 20 to 25 minutes.
Before serving, drizzle lightly with olive oil.