Preheat the oven to 220°C.
Mix the flour, salt, sugar, and yeast in a bowl.
Add 300ml warm water and 100ml olive oil to a well in the center and form a soft dough.
Knead the dough on a floured surface for 10 minutes until elastic, then let rise for one hour in an oiled bowl.
Sauté sliced onions and thyme in olive oil for 25 minutes until golden.
Stir in sugar and vinegar, cook for three minutes, season, and remove from the pan.
Cook the pancetta and rosemary in the same pan until crisp, then set aside.
Knock back the risen dough and stretch it into a long oval shape.
Place on an oiled tray and let rest covered for 30 minutes.
Dimple the dough, top with onions, olive oil, and salt, then bake for 20 minutes.
Add blue cheese, pancetta, and rosemary, then bake for two more minutes until the cheese melts.
Garnish with fresh rosemary and serve immediately.