Make dough for crackers. In a food processor, pulse together all-purpose flour, whole wheat flour, butter, salt, and cheddar until mixture resembles coarse sand. Add cold water and pulse just until dough comes together. Shape dough into a disc and wrap in plastic wrap. Chill for 1 hour.
Preheat oven to 350 degrees F. Line 2 baking sheets with parchment paper.
Lightly dust a clean work counter with flour. Roll out cracker dough until paper-thin, about 1/16 inch thick. Transfer dough to the prepared baking sheets. Use a sharp knife or pizza cutter to cut dough into 1-inch square crackers. If desired, use the blunt end of a toothpick to make a small hole in the center. Bake crackers for 15 minutes or until golden brown. Remove from oven and let cool.
Separate crackers and place them in a large bowl. Mix melted butter with chili powder, cayenne, onion powder, dried parsley, dried dill, garlic powder, and sugar. Drizzle seasoned butter over crackers, tossing to coat. Microwave the crackers for 3 minutes, tossing every minute.
Spread crackers on clean parchment paper in an even layer and let cool completely.
Notes
You can bake the crackers the day before and season them the following day.