Step 1: Prepare the Dough

1. In a mixing bowl, whisk together the flour, salt, garlic powder, smoked paprika, and baking powder.
2. Add the cold cubed butter and use a pastry cutter or fingers to blend it into the dry ingredients until the mixture resembles coarse crumbs.
3. Stir in the shredded cheddar and grated Parmesan cheese.
4. Pour in the sourdough discard and mix until a cohesive dough forms, adding water as needed.

Step 2: Chill the Dough

1. Shape the dough into a disk, wrap it in plastic wrap, and refrigerate for at least 30 minutes.

Step 3: Roll and Cut

1. Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.
2. Roll out the dough on a lightly floured surface to about 1/8-inch thickness.
3. Cut the dough into desired cracker shapes using a pizza cutter, knife, or small cookie cutter.
4. Transfer the crackers onto the baking sheet and sprinkle with coarse salt.

Step 4: Bake to Perfection

1. Bake for 18-22 minutes, or until golden brown and crisp.
2. Let cool completely before storing.