Pre-heat oven to 180. In a microwave-proof dish, microwave the butternut on high for about 8 minutes, until soft.
Meanwhile, in a large frying pan on med-high heat, add the butter and olive oil. When hot add the onions and sugar and fry gently for 10 minutes until lightly golden.
While the onions and butternut cook, grease and lightly flour your baking tray and lay the puff pastry on the floured surface. Make a 1cm border around the pastry base with a fork, and several fork stabs over the surface of the tart (to stop it puffing up in the middle).
When the onions are cooked, remove from the stove, add in the cooked butternut, toss gently and then top the pastry with the crumbled cheese, onions and butternut and season with salt and pepper.
Bake for 20-25 minutes until the pastry is golden and crisp around the edges. Scatter the pine nuts over the tart and leave for a further 5 minutes.
Serve with a green salad and/or slivers of seared beef or roast chicken.
Reprinted with permission of Sarah Graham.
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