If you are unable to find Oaxacan cheese, you can substitute mozzarella. The tomato sauce can be made the night before and refrigerated. Remove it from the refrigerator when you remove the dough to come to room temperature. If you are nervous about cracking an egg directly onto the pizza and breaking the yolk, we recommend breaking it into a small cup or ramekin first and then gently pouring it into the well in the pizza. If you have a smaller oven, you may need to make one pizza at a time.