This Upside-Down Onion Tart is something you can throw together with "bare-bones" ingredients. You only need two essential ingredients: puff pastry and onions!
Now, if you do not consider puff pastry a pantry, or rather a freezer essential, then you should. Having a couple sheets of puff pastry around is like having an insurance policy...it always comes in handy. It's not only perfect for throwing together a quick and fruity dessert, like this gorgeous Winter Citrus Tart with Rosemary Whipped Cream, but it's also a lifesaver if you want to whip appetizers, or top a soup or stew, like this Irish Beef Stew with Puff Pastry Dippers, or even use as a make shift pie crust, like I did when I made these Mini Corned Beef Pot Pies. I am simply never without a box (or two) in my freezer!
And hopefully, we all have onions in our pantry! Not only are they the base of so many dishes, but they are even better when they are allowed to shine as the featured ingredient, such as in this absolutely incredible Onion Soup Lyonnaise-Style. Trust me when I say that soup has become such a staple, and I am never without the ingredients to make it.
This tart is another way for the humble onion to play center stage. Pair this with a green salad, or even on the side of any beef dish, and you're in for a true caramelized onion delight!
Upside-Down Onion Tart
Adapted from River Cottage Veg
by Hugh Fearnley-Whittingstall
About 7 ounces/200g all butter, ready made puff pastry
3 or 4 onions (about 12 ounces/350g)
1 tablespoon butter
1 tablespoon canola or olive oil
salt and ground pepper, to taste
1 tablespoon balsamic vinegar
Optional: Sprinkling of thyme leaves and/or cheese of your choice. I used opted for a few crumbles of blue cheese
Preheat the oven to 375F. Roll out the pastry on a lightly floured surface to a 1/8 inch thickness and cut out an 8-inch circle. Wrap the pastry disk and place it in the fridge.
Peel the onions and slice each one into 6 or 8 wedges, keeping the root end attached. Heat the butter and oil in an 8-inch tarte tatin pan or ovenproof frying pan over medium heat. Add the onions, arranging them roughly in a pinwheel pattern. Sprinkle with salt and pepper and cook for 15 to 20 minutes, turning once or twice, until they are fairly tender and starting to caramelize around the edges.
Trickle the balsamic vinegar over the onions and cook for a couple of minutes more, so the vinegar reduces a little. Remove from the heat and make sure the onions are fairly evenly spread around the pan.
Lay the pastry disk over the onions and put the pan into the oven. Bake for 20 minutes, until the pastry is fully puffed up and golden.
Invert the tart onto a plate so the sticky caramelized onions are facing up, on top of the crispy pastry. Serve right away, ideally with a green leafy salad. You could also crumble or grate over a favorite cheese.