Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper to prevent sticking.
Combine dry ingredients. In a large mixing bowl, mix the flour, salt, and mustard powder.
Add cheese and butter. To the flour mixture, add the grated Cheddar and the butter (cut into small cubes). Use your fingers or a pastry cutter to blend until the mixture looks like coarse crumbs.
Add the eggs. Crack the eggs into the bowl and mix everything together until it forms a dough. It may feel a little sticky, but that's okay.
Roll out the dough. Transfer the dough to a lightly floured surface. Roll it out as thin as possible – the thinner, the crunchier!
Cut into shapes. Use a sharp knife or cookie cutter to cut the dough into your favorite shapes. I like using small squares, but you can go for whatever shape you prefer.
Prepare for baking. Place the crackers on the prepared baking sheet and sprinkle a little sesame or poppy seeds on top for extra flavor and crunch.
Bake. Pop the tray into the oven and bake for 12-15 minutes or until the crackers are golden brown and crispy.
Cool and serve. Once baked, let the crackers cool on a wire rack. Serve and enjoy!