Pumpkin and caramelized onion Cocas (Valencian pizza)

Ingredients

• 10 grams/0.02 lb of fresh yeast (or 7-gram sachet fast-action dried yeast)
• 330 ml/11 fl. oz. lukewarm water
• pinch sugar
• 500 g/1.1 lb. of plain flour (plus a little extra for dusting)
• 1 tbsp extra virgin olive oil
• 6 grams of sea salt (crushed fine)
• 300 grams/ 0.66 lb. of butternut squash (cut into small ½-inch thick wedges)
• 1 red onion (cut into thin wedges)
• 40 ml/1.35 fl.oz. extra virgin olive oil
• A few sprigs of rosemary (or thyme)
• 20-30 grams of crushed pistachio nuts
• Crushed chili flakes
• Some alfalfa for garnish (optional)