Red onion tarte tatin with rye pastry

I was never a pie/tart maker (one look at the blog index can confirm that), but I do love pies and tarts: I just don’t have much time for them, I guess. Two things that have helped me with this matter is making the pastry in one day and assembling and baking the pie on the other, or keeping an extra batch of pastry in the freezer – nothing like having the pastry ready when you find beautiful veggies or fruits in the market: lunch, dinner or dessert are halfway there.

This pastry is delicious and flaky, very similar to the corn flour pastry I posted a while ago. The onions not only make the tarte tatin beautiful but also very flavorsome: the time in the stove top and then in the oven transform their acrid flavor into something sweet and mellow.

Red onion tarte tatin with rye pastry
own recipe

Pastry:
¾ cup (105g) all purpose flour
3 tablespoons (30g) fine rye flour
¼ teaspoon table salt
¼ cup unsalted butter, chilled and cubed
3 tablespoons sour cream, chilled*
1 tablespoon iced water

Filling:
2 red onions (approximately 250g/9oz in total)
2 tablespoons unsalted butter
½ teaspoon olive oil
5 fresh thyme sprigs
½ teaspoon demerara sugar
2 teaspoons balsamic vinegar
2 teaspoons dry red wine
salt and freshly ground black pepper

Start by making the pastry: in a food processor, pulse all purpose flour, rye flour and salt until well combined. Add the butter and pulse a few times until mixture resemble coarse breadcrumbs. Mix sour cream and water in a small bowl, then with the motor running, gradually add the mixture and process just until a dough forms. Form dough into a ball, wrap in plastic wrap and refrigerate for 1 hour.

20 minutes before the end of the resting time of the pastry, preheat the oven to 180°C/350°F and start prepping the onions: peel them and cut them in half lengthwise. Then slice the onions in to 1cm (roughly ½in) half-moons – if the slices are too thin they will melt in the oven. Set aside.
Heat a 22cm (9in) frying pan over medium heat – for this recipe you need a frying pan that can go into the oven. Add the butter and the olive oil, followed by the thyme sprigs – this way they will be on the top of the tart once you invert it. Remove the frying pan from the heat for one moment and arrange the onion slices on top of the thyme, placing the slices close together, for they will wilt slightly when cooked - cover the entire frying pan with the onion slices. Put the pan back on the heat and cook for 10 minutes, shaking the pan slightly instead of stirring the onions, to avoid them sticking to the bottom, but keeping them in place. Sprinkle with the sugar, drizzle with the balsamic vinegar and the wine, season with salt and pepper and cook for another minute. Turn off the heat and set aside.

Place the dough onto large piece of baking paper, cover with another piece of paper and roll into a rough 24cm (9in) circle – work fast in order to keep the pastry chilled. Peel off the paper from the top, then roll the pastry into the rolling pin, very gently, then unroll it on top of the onions (be careful since the pan will still be hot). Tuck the pastry in, make a small hole in the center of the pastry so the hot air can escape, then bake the tart for 30-35 minutes or until golden brown. Remove from the heat and very gently loosen the pastry from the edges of the pan. Top the pan with a plate and carefully unmold the tart – don’t worry if any onion bits get stuck in the pan, just loosen them up with a spatula and arrange them back on top of the tart. Serve with a green salad.

* homemade sour cream: to make 1 cup of sour cream, mix 1 cup (240ml) heavy cream with 2-3 teaspoons lemon juice in a bowl. Whisk until it starts to thicken. Cover with plastic wrap and leave at room temperature for 1 hour or until thicker (I usually leave mine on the counter overnight – except on very warm nights – and it turns out thick and silky in the following morning; refrigerate for a creamier texture)

Serves 4 with a green salad on the side