Preheat oven to 450 degrees. Place oven rack in lower third of oven.
Mix together flour, Parmesan, sugar, salt, basil, thyme, and garlic powder with a fork.
Stir in olive oil and water until a ball of dough forms.
Place a sheet of parchment paper on a flat surface; sprinkle lightly with flour.
Transfer half of the dough to the parchment paper and shape into a rough rectangle.
Using a rolling pin, roll out dough until it's about ⅛-inch thick (or less).
Sprinkle dough with half of the toppings, if using, then lightly press toppings into dough using your hands. Prick dough all over with a fork.
Use a pizza cutter to cut the dough into rectangles about 1 x 2-inches. (No need to measure and don't worry if some of your crackers aren't perfectly rectangular. They'll still taste great.)
Transfer parchment paper to a baking sheet, then separate crackers slightly.
Repeat process with remaining dough.
Bake crackers until browned on edges, about 12 to 15 minutes. (If some of the crackers on the outside of your pan brown faster, remove them so they don't burn, then continue baking other crackers.)
Cool crackers on baking sheet, then serve immediately or store in an airtight container until ready to use. Enjoy!