Preheat oven to 375°F.

Fill a 2-cup measuring cup with ice. Top measuring cup off with water (at least ½ cup). Set aside. Roughly cube butter into ½-inch to 1-inch pieces.

Add flour and salt in a large mixing bowl, tossing to combine.

Add cold, cubed butter to your flour mixture.

Work butter cubes into the flour, using your fingertips to smash the butter into little flakes. Every piece of butter should be smeared and coated with flour before you begin to add the water.

Turn dough out onto a lightly floured counter and give the dough several kneads to completely combine. The dough should be soft and slightly tacky, but not sticky.

Divide the dough into two equal pieces.

Form each piece into a flat disk and wrap each one in plastic wrap. Refrigerate for at least 30-minutes, or overnight.

While the dough is resting, prepare the quiche filling as instructed below.

Remove both pieces of dough from the fridge, and roll each into a flat circle, approximately 12-inches in diameter and ¼-inch thick.

Place dough into pie dishes, and prick with a fork all over. Trim the excess dough with a sharp knife and discard.

Cover each pie dough with aluminum foil and place pie weights or 2 cups of dry rice, sugar, or beans on top of each one.

Par-bake crusts for 15-minutes, and remove aluminum foil and pie weights. Bake for an additional 5 to 8-minutes until slightly blonde, but not cooked all the way through. (Prepare quiche filling while pie crusts are par-baking.)

Remove and allow to cool slightly.

While pie crusts are par-baking, heat a large, heavy bottom stainless or cast iron skillet over medium heat. Add sliced bacon and cook, stirring frequently until crispy and fat has completely rendered.

While bacon is cooking, combine eggs, egg yolks, heavy cream, and measured salt and pepper to a medium bowl, stirring to combine.

Remove the bacon, reserving the fat in the pan. Add bacon pieces to the custard mixture. Increase heat to medium-high.

Add leeks to the skillet with a small pinch of kosher salt. Sauté until soft and some color begins to form, approximately 5 to 7-minutes. Season to taste with black pepper and white pepper.

Transfer cooked leeks to custard mixture, stirring to combine.

Add ⅔ of both the shredded gouda and white cheddar, reserving the remaining ⅓ to sprinkle over the top before baking.

The day before making the quiche (or as soon as 4-hours before serving your quiche), add buttermilk and heavy cream to a dish, stirring to combine. Loosely cover and Rest for 3-hours (up to overnight) on the counter.

Add salt and chives to the crème. Transfer to a blender or immersion blender cup and blend until smooth, approximately 2-minutes.

Transfer sauce to a bowl or a squeeze bottle, and refrigerate until cool and thickened, at least 1-hour.

Use to garnish your plate, or drizzle directly over quiche slices.

Preheat oven to 350°F (if preheated from par-baking the crusts, reduce temp to 350°F.)

Bake for 35 to 40-minutes until golden brown, and the middle has just barely begun to set.

Remove from oven and allow to cool for 10 to 15-minutes before slicing and serving.