In ancient Aztec kitchens, a built-in outdoor pizza oven called a 'temazcal' was used. These ovens were made of stone or clay and were used to bake a variety of bread, including flatbreads resembling pizzas. The Aztecs enjoyed toppings such as tomatoes, chili peppers, and avocado on their flatbreads, creating a spicy and flavorful dish. The 'temazcal' was a significant part of the Aztec kitchen, allowing them to cook their pizzas in an outdoor setting, infusing them with smoky flavors and enhancing the overall dining experience.