Prep your tools. Line two baking sheets with parchment paper.
Lightly flour your work surface. Preheat the oven to 350°F (175°C).
Combine dry ingredients. In a large bowl, whisk the flour, cornstarch, baking powder, salt, and any spices you’re using. The cornstarch helps make the crackers extra crisp.
Cut in the butter. Add the cold butter cubes.
Use your fingertips or a pastry cutter to work the butter into the flour until the mixture looks like coarse crumbs with some pea-sized bits. Keep it a little chunky for flakiness.
Add the cheese. Stir in the grated cheddar until evenly distributed. The cheese should be well coated in the dry mix to prevent clumping.
Bring the dough together. Sprinkle in 2 tablespoons of ice water.
Use a fork to toss the mixture until it starts to clump. If it’s still dry, add up to 1 more tablespoon water. Stop as soon as the dough holds when pressed.
Chill briefly. Press the dough into a flat disk, wrap it, and chill for 15–20 minutes.
This keeps the butter cold and makes rolling easier.
Roll it out. Place the chilled dough on a lightly floured surface. Roll to about 1/8 inch (3 mm) thick. Rotate the dough and dust lightly with flour as needed to prevent sticking.
Cut shapes. Use a small cookie cutter, a pastry wheel, or a knife to cut 1-inch squares or any shape you like.
For the classic look, poke a small hole in the center with a skewer. Transfer pieces to the lined baking sheets.
Finish and season. Brush lightly with the egg wash if you want a glossy finish. Sprinkle a pinch of flaky or fine salt over the top.
Go easy—the cheese brings salt too.
Bake. Bake for 12–16 minutes, rotating the pans halfway. They’re done when the edges are golden and the centers are set. Thinner pieces bake faster, so keep an eye on them.
Cool completely. Let the crackers cool on the tray for 5 minutes, then move them to a wire rack.
They will crisp up more as they cool. Wait until fully cool before storing.
Taste and adjust. Try one. If you want more snap next time, roll the dough thinner or add an extra minute in the oven.
For more cheddar punch, use extra-sharp cheese.