Putting It All Together

Roll the dough, about 1/8” thick, onto a sheet of lightly-floured parchment and cut the pastry into a rectangle about 12” long x 7” wide. With your knife, gentle etch a 1-inch border around the pastry, without cutting through the dough.

Brush the border with the egg; this helps glue the border when you fold it over, ensuring it stays in place during baking. At each corner, make a small diagonal cut to allow the edges to fold over without overlapping or bunching.

Gently fold the border inward along the cuts and press the edges lightly to seal them. The corners should align smoothly without bunching to form a clean, raised edge for the tart.

Using the back of your knife, score the pastry in 1/4 intervals, around the border. This helps the pastry rise evenly.

Cover with plastic and refrigerate for 30 minutes.

Preheat the oven to 425℉.

Remove the tart from the fridge and prick the base several times with a fork (to prevent the pastry from buckling) then sprinkle with Parmesan cheese. Brush the tart’s edges with the egg.

Transfer the parchment-lined tart to a baking sheet and bake for 15-20 minutes, or until the edges are golden, rotating the pan once.

Reduce the oven temperature to 350℉.

Combine the Gruyère and goat cheese in a small bowl and thin with 2 - 3 Tbsp of milk, until spreadable. Set aside.

Wipe the mushrooms clean with a damp cloth or rinse briefly in cold water and pat dry. Shiitake mushroom caps can be left whole but remove the tough stems. Tear chanterelles and oyster mushrooms in half or, if small, keep whole. Slice or quarter the button mushrooms.

Melt 1 Tbsp butter in a medium skillet over medium heat; add the shallots, thyme and a pinch of salt and cook, stirring frequently, until the shallots are translucent. Transfer to a medium bowl.

Cook the mushrooms in batches, starting with the heartier ones and ending with the delicate, quick-cooking mushrooms. Heat 1 Tbsp each butter and oil in the same skillet, over medium-high heat. Add a handful of mushrooms to the skillet along with a pinch of salt, being mindful not to crowd the pan. Shake the pan to coat then cook, undisturbed, until the mushrooms have coloured on one side; adjust the heat as necessary to prevent burning. Toss the mushrooms and continue to cook until brown all over. Add 1 Tbsp vinegar, 1/2 tsp of soy sauce, stir and allow the liquid to evaporate.Transfer to the bowl of cooked shallots.

Cook the balance of mushrooms in the same manner, starting with butter and oil and ending with the vinegar and soy sauce after the mushrooms have browned. If the pan becomes too dry, add a splash of water.

Combine the cooked mushrooms and shallots; taste and season with additional soy or vinegar if desired.

Spread the cheese mixture over the base of the partially cooked tart. Top with the shallot and mushroom mixture.

Bake on a parchment-lined baking sheet for about 15 minutes or until warmed through.