To cook in a tagine, place the food in the pot, cover and cook over medium-low heat. Use a heat diffuser for electric or smooth-top stoves to prevent the tagine from touching the hot surface directly.
Before cooking in a new tagine, season the pot by soaking overnight in water, placing it in a cold oven, and turning the heat to 300 degrees Fahrenheit. Bake the pot for two hours, turn off the heat, and allow it to cool in the oven. Remove the tagine from the oven, wash it by hand, and coat the inside with olive oil.
Place a layer of onions or other vegetables in the bottom of the tagine to prevent meat from sticking. Layer the meat and more vegetables in the pot. There is no need to brown the meats you cook in this pot. Mix the spices for even distribution, and sprinkle them over the meat and onions. Layer other vegetables on top of the meat, and top with additional spices. Add the full amount of water and oil called for in the recipe.
Place the tagine on a cold stove and turn the heat to medium-low. Once the water begins to simmer, a process that sometimes takes up to 30 minutes, adjust the heat as necessary to maintain a slow simmer, and follow the recipe directions for slow cooking.