Preheat the oven to 400 degrees F. Line a baking sheet with parchment paper. Wrap a yardstick or ruler with aluminum foil and suspend it between two 28-ounce cans.
Sprinkle 1/2 cup of the shredded Cheddar on the baking sheet to form a circle 6 inches in diameter. Repeat with another 1/2 cup of cheese, making 2 circles. Bake the first batch until the cheese melts and turns light brown, 6 to 8 minutes.
Using a spatula, transfer the cheese circles to the suspended yardstick and drape them over to form taco shells. Let them hang until firm, then carefully remove. Repeat with the remaining cheese.
Fill the shells with your favorite taco fillings.