In the mixing bowl of the stand mixer, place butter, bread flour, and salt, and attach the paddle. Place bowl and its contents in freezer for 10 minutes to chill.

Remove from the freezer and assemble on the stand mixer. Beat ingredients on medium low until crumbly. Slowly add water and continue to beat until dough forms. Add additional cold water if necessary. Wrap dough in plastic and let chill for at least 1 hour or up to 4 hours. (This helps to prevent cracking.)

Preheat oven to 400°F. On a floured work surface, roll out down to 1/4” thickness. Lay dough over a 9” spring release pan and carefully work dough into the corners and up the sides of the pan, letting the excess hang over the edge. Place in the refrigerator for 10 minutes to firm up.

Layer dough with foil, and fill with baking weights, place in the oven and bake for 20 minutes.

Remove foil with weights and bake for 5 minutes longer.

Turn oven down to 325°F.

In a sauce pot on medium heat, add extra virgin olive oil, onions, mushrooms, leeks, and garlic. Sweat vegetables for 5 minutes or until soft. Season with half the salt and black pepper. Add thyme and parsley, stir to combine.

In a blender add eggs, remaining salt, and yogurt. Blend mixture on low until smooth and well combined.

Add mushroom and leek mixture directly into pâte brisée, add Gruyère, and pour egg and yogurt mixture over everything. Carefully swirl ingredients to mix well.

Bake for 30-40 minutes or until eggs are just set, about 175°F.

Let quiche rest for 30 minutes or overnight to set.

Serve warm or chilled.