Mix all of the dough ingredients in a bowl with a dough whisk.

Knead the dough briefly with your hands to just incorporate all of the ingredients. The dough should be tacky but not sticky. If it is too dry, add water, one tablespoon at a time. My original dough was really dry, but, after an overnight rest in the refrigerator, it behaved amazingly well.

Place the dough into an oiled bowl and turn it to coat with oil. Cover with plastic wrap and refrigerate for 8 to 24 hours.

Beat the butter and flour in the bowl of a stand mixer with the paddle attachment for about a minute.

Place the butter on top of a sheet of plastic wrap and place another sheet on top.

Roll the butter out to a 8 by 9 inch rectangle. Use a ruler to make sure the edges are straight and the corners are sharp.

Wrap and place the butter block in the refrigerator with the dough to chill.

Spread the baking soda onto a baking sheet and bake for one hour in a 250 degree oven.

Cool and store in an airtight container.

Turn the cold dough out onto a lightly floured surface.

Roll it into a 10 inch by 15 inch rectangle. Make sure the corners are squared by pulling the dough with your hands. The 15 inch edge of the dough should be facing you.

Place the butter block over the right ⅔ of the dough, leaving a one inch border on the outer edges.

Fold the left portion of the dough that does not have butter on it over half of the butter block. Fold the right portion of the dough, which has butter on it, over the dough that has just been folded over the dough. You should have a tri-fold that is dough, butter, dough, butter, dough. Squeeze the edges together, wrap with plastic wrap, and refrigerate for an hour.

Remove the dough from the refrigerator and place it on a lightly floured surface.

Roll the dough out into a 10 inch by 20 inch rectangle with the 20 inch side facing you. Mentally divide the dough into fourths and fold each outer fourth into the middle. Then fold the dough over itself so that you have a "book" of four layers. Press the layers together and wrap with plastic wrap and refrigerate for one hour.

Remove the dough from the refrigerator and place it on a lightly floured surface.

Roll the dough out into a 10 inch by 15 inch rectangle with the 15 inch side facing you. Do a trifold, folding the left and right sides over each other so that you have three layers of dough. Press the layers together and wrap with plastic wrap and refrigerate for at least two hours, and up to 24 hours. I let mine rest over night in the refrigerator.

Line two rimmed baking sheets with parchment and set aside.

On a lightly floured surface, roll the dough out to a 15 inch by 18 inch rectangle. I found lightly dusting both sides of the dough with flour, flipping it between rolls, and letting it rest for a few minutes. made this easier. Stretch the dough to make a rectangle with corners.

Cut the rectangle in half widthwise, to make two 15 by 9 inch strips. Cut each strip into three equal rectangles.

Cut the rectangles diagonally in half to create triangles.

Beginning at the bottom of each triangle, roll up the dough, tucking the pointy part under so it doesn't go rogue (this is always something I forget), and place them on the baking sheets.

Cover the croissants with oiled plastic wrap, and let rise until very slightly puffy, for about 2 hours.

Preheat the oven to 425 degrees F.

Mix the baked baking soda with 8 cups of cold water.

Dip each croissant into the water, let the excess drip off, and place them back onto the baking sheets.

Brush with egg wash and sprinkle with the salt and seeds.

Bake for about 20 minutes, rotating the baking sheets about halfway through. The finished croissants should be a deep golden brown.

Cool on a wire rack for at least 10 minutes.

Leftovers can be warmed in a 350 degree oven for about 5 to 10 minutes.