Step 1

Put one oven rack two spaces below the broiler and the other on the second level from the bottom. Put your cast iron skillet on the bottom rack and heat the oven to 450°F (232°C). Let the skillet heat for 10 minutes.

Step 2

Wear silicone gloves to take the skillet from the oven to the stovetop. Pour the sourdough starter discard into the skillet and tilt it in circles to spread the starter evenly across the bottom of the skillet. (If your starter is thick, spread evenly into the bottom of the pan with an off-set spatula.) Put the skillet back in the oven for 10-15 minutes. Check it at the 10-minute mark to prevent the crust from burning.

Step 3

Once more, use silicone gloves to remove the skillet from the oven. Switch the oven broiler to LOW. Add your toppings onto the pizza crust. Move the skillet under the broiler for 1-2 minutes, keeping an eye on it to avoid burning. Remove the skillet from the oven and transfer the pizza to a cutting board. Serve right away.