Preheat the oven to 180°C or 350°F. Line a baking tray with baking paper.
Arrange the pumpkin pieces on the baking tray. Drizzle with 2 tablespoons olive oil and season with sea salt and pepper. Place the tray in the oven to roast for 25 minutes.
Whilst the pumpkin is roasting, heat the remaining olive oil in a non-stick frying pan over a medium heat. Add the sliced onion to the pan and cook for 6-7 minutes until softened. Add the balsamic vinegar and coconut sugar and stir to coat. Reduce the heat slightly and cook for a further 7-8 minutes or until the onion is golden and caramelised.
Meanwhile, crack the eggs into a large mixing bowl and season with sea salt and black pepper. Whisk the egg mix until light and fluffy. Add in the chopped rosemary and whisk again.
Line a baking dish or quiche dish with baking paper. We used a 20cm by 30cm dish. Spread the shredded spinach leaves and half of the roasted pumpkin and onion across the base of the dish. Pour the egg mixture evenly over the top. Place the remaining pumpkin and onion on top of the egg mix. Crumble the goat's cheese over the top.
Place the frittata in the oven to bake for 25 minutes.
Keep stored in an airtight container in the fridge for 4 days.
