1. Preheat the oven to 200°C. Line a baking tray with baking paper, add pumpkin, olive oil, fennel seeds, vegetable broth, salt and pepper, toss to combine and bake for 15 mins.
2. Meanwhile, peel, halve, and very thinly slice the onions into half moons, keeping the moons intact. Place the onion half moons on the pumpkin just barely overlapping and brush lightly with olive oil.
3. Score each pastry sheet with a 1cm border.
4. Layer the pumpkin over the pastry, place onion slices on top then give the onions a drizzle with a little olive oil.
5. Place the tarts on a large oven tray lined with non-stick baking paper. Cook for 10 minutes, then remove from the oven, add the goat cheese and thyme sprigs then return to the oven to bake for another 5 minutes until everything is golden and toasted.
6. When ready to serve, top with zucchini flowers, and cut into wedges.