Add the flour, starter, water, and salt to the bowl of a stand mixer. Mix on low with the dough hook until combined.

Increase the speed to medium, and add your butter. Mix until the dough pulls away from the sides of the bowl.

Cover your bowl and let the dough rise at room temperature for about 8 hours (based on a 71-72° home/ambient temperature - if your environment is colder, proof for longer).

Cover the bowl and place the dough into the fridge to cold-proof overnight.

The next day, prepare your lamination butter. Allow the butter to soften at room temperature. Take a large piece of parchment paper and fold it into a 6-8” packet. Place the butter inside the parchment and roll/press it into a 6-8” square using a rolling pin.

Place the butter packet into the fridge. When you begin the lamination process, you want the butter to be cold but still malleable.

Roll your dough into a 12” square on a floured surface. Place the cold butter sheet on the dough at a 45° angle so it forms a diamond on top.

Bring the corners of the dough to the center of the butter, sealing the butter inside. Press the edges of the dough together to create a tight seal.

Carefully and evenly, roll the dough into a rectangle (roughly 9”x18”). As your roll, be mindful not to let the dough rip or tear - you want the butter to stay encased at all times.

After creating a thin rectangle, fold the dough over itself in thirds, creating a pamphlet. Cover with plastic wrap and refrigerate for 30 minutes.

Repeat the laminating process 3 more times, with a 30-minute rest in the fridge between each turn.

Allow the dough to rest in the fridge for at least 2 hours (and up to 3 days) before using.

When you’re ready to bake, roll your dough to the thickness you prefer.

Brush with egg wash before baking for the perfect shine.

Bake at 400°F until golden brown (time will vary based on how you shaped your dough and the fillings you use). I made 8 square pastries and baked them for 20-25 minutes.