Crust

1. Add flour and salt to a food processor. Blend for a few seconds. Add butter and blend for a few seconds at a time until butter is the size of peas. Add the egg, water, and Parmesan. Mix until the dough starts to take shape. Remove dough from food processor and shape into a disc. Wrap dough and refrigerate for 30 minutes.
2. Place rack in the middle of the oven. Preheat the oven to 200°C (400°F).

 Filling

1. Heat 30 mL (2 tbsp.) butter in a 25-cm (10-in.) non-stick, ovenproof skillet and brown mushrooms over high heat. Set aside on a plate. In same skillet, heat remaining butter over medium heat and fry onions and garlic for 15 minutes or until softened and coloured.
2. Add the reserved mushrooms, balsamic vinegar, Parmesan, and parsley. Season with salt and pepper. Set aside.
3. On a floured work surface, roll out the dough into a 25-cm (10-in.) round.
4. Top mushroom mixture with dough. Bake in the oven for 20 minutes, or until crust is golden brown. Turn over and out onto a serving dish.

Chef's secret

If you don't have this type of non-stick skillet, transfer the mushroom mixture into a 25-cm (10-in.) pie pan and top with dough.

Nutrition tip

Serve the tarte tatin at cocktail hour, or as a main dish accompanied by an arugula salad with shaved Parmesan.