Block/pack puff pastry
2 red onions
Vinegar (preferably balsamic, but it doesn’t really matter)
2 sweet potatoes
Peel the sweet potatoes and slice lengthways into 6 or 8 wedges. Put in a bowl with olive oil and rosemary, and toss to coat. Lay out on an oiled baking tray with a couple of unpeeled garlic gloves tucked in amongst them. Bake at 200 degrees for about 45 mins. They’ll need turning over once or twice.
Roll out the puff pastry, and score a 1cm border round the edge. Prick the middle all over with a fork, and bake for 10mins, 200 degrees, until crisp. Finely chop the onions, and sauté over a medium heat in the olive oil until translucent. Sprinkle about a dessert spoon of sugar over the onions and about 2 dessert spoons of vinegar, and whack the heat right up to caramelise the onions. Put the spinach in a pan with a lid with a splash of water, and wilt it right down. Drain, and (using back of a spoon or your hands) squeeze as much water out as possible. Spread the onion mixture over the tart, followed by the spinach. Crumble or slice the goat’s cheese, and add torn mozzarella, if you like.
Bake for another 15mins, until puffed and golden round the edges, with the cheese all melted and bubbling. Squeeze the garlic from its skin and serve alongside the tart and wedges, and some peas or broccoli.