First, mill your flour. Add ¼ tsp salt and ¼ tsp onion powder to the flour.
Weigh out 8oz of cheddar cheese. Using a food processor fitted with the shredding attachment, shred your cheese. Remove the shredding attachment and replace it with the blade. Add in the cubed butter and process briefly until the cheese and butter form a cohesive mass. Don’t overmix.
Next, add in the flour. Pulse until a crumbly dough forms. Fill a cup up with water and ice so you have ice water ready to go. With the food processor running, use a tablespoon to drizzle in 2 tablespoons of water into the dough until it comes together; stop as soon as it does.
Chill The Dough - Place a piece of parchment paper on the counter. Transfer the dough onto the parchment, and form it into a thin disk with your hands. Use the parchment paper edges to fold over the dough to wrap the disk tightly. Flip it over so the folded edges are down, then press the dough into the edges of the parchment paper. Transfer it to the fridge for 30 minutes.
Roll Out Your Dough - Prepare 2 sheet pans with parchment paper. On a floured surface, use a floured rolling pin to roll the dough into a big oval, about 1/6 inch thick. I like to use a rolling pin with measuring disks for this.
Using a pizza cutter, first cut the raw edges to make rustic crackers. What will remain is a nice perfect rectangle, and you can then cut out perfect cracker squares, according to your preferences. Place all the crackers on a sheet pan, poke holes with a fork or toothpick, and brush with a beaten egg. Sprinkle wth course salt.
Bake at 350°F, or 175°C for about 20 minutes or until golden.