Tarte Tatin of Onions

Method

1. Prepare the pâte brisée: In a cold bowl, combine cold butter (straight from the freezer) and flour. Quickly rub the butter into the flour until it resembles coarse sand.
2. Add ice-cold water little by little, just enough to bring the dough together. Do not overwork.
3. Turn the dough onto a work surface, knead briefly until smooth, then wrap and refrigerate for 30 minutes.
4. Preheat the oven to 180°C (static). Line a round baking pan with parchment paper (wet the paper slightly to help it stick).
5. For the onion base: Sprinkle brown sugar evenly over the bottom of the pan. Add a few drops of apple balsamic vinegar, salt, pepper, and a few small knobs of butter.
6. Slice the onions into rounds about 0.5 cm thick. Arrange them tightly in the pan, filling any gaps with sliced shallots.
7. Season the top with salt, pepper, and fresh thyme leaves (or oregano, sage, or rosemary).
8. Remove the chilled dough from the fridge. Briefly knead to soften slightly, then roll it out between two sheets of parchment paper to a thickness of 2–3 mm.
9. Place the rolled dough over the onions, tucking the edges inside the pan. Prick the dough with a fork.
10. Bake for about 30 minutes, until the crust is golden and the onions are caramelized.
11. While the tarte bakes, make the gorgonzola fondue: Heat fresh cream in a saucepan until it reduces by about one quarter. Crumble in the gorgonzola (or blue cheese) and whisk until smooth. Keep warm.
12. Let the tarte cool slightly, then invert it onto a large plate. Serve with the gorgonzola fondue drizzled over or on the side. Garnish with fresh thyme.