Firstly, Mill the flour, cover and place in the fridge to cool.

Once the freshly milled flour is cool, add starch and salt and then mix to combine.

Grate the frozen butter into the flour mixture. Mix the butter shreds in with the flour mixture to coat all the butter. Try to keep the butter separated as much as possible to keep it evenly distributed in the flour. This is a dry mixture at this point.

Then, once the butter is coated and separated in the flour, slowly add the cold water. Add half at a time until the dough starts to come together. It should still seem a bit dry and crumbly at this stage.

Lightly flour your work surface (I like to use a silicone pastry mat that has a grid on it for these next steps.) Also, a bench scraper is your best friend to work with the dough, get it off the work surface, and not warm it up too much.

Take the dough to the work surface, it should still be a bit crumbly at this stage, and it will come together as you work with it.

Knead the dough one or two times to gather into a ball. Don't overwork the pastry and try not to let the warmth of your hands melt the butter. (If it starts to warm up or melt at any point during working with the dough, just pop it back in the fridge for 15 minutes or so.)

Flour your hands and a rolling pin to prepare for this next step.

Pat the dough into a rectangle, and begin rolling the dough into a 6"x 20" rectangle, keeping the short side of the rectangle in front of you.

Then, using your bench scraper pull the top ⅓ of the dough down over to the middle of the dough.

Next, using your bench scraper, pull the bottom ⅓ of dough up over the part you just folded. This is like a tri-fold letter, which is how it gets the name a "Letter Fold."

The next step, take the folded up dough, and turn it 90 degrees. Now, you will roll it back out into a 6"x 20" rectangle again.

Then, once rolled out preform another letter fold.

Turn dough 90 degrees again. Do this process of rolling out into a rectangle then letter folding a total of 4 times.

On the last letter fold, keep it folded up, and wrap in plastic wrap.

Chill the dough in the fridge for at least 30 minutes before using in any recipes.