The lush Azores Islands, an autonomous region of Portugal located in the middle of the Atlantic Ocean, were formed by colliding tectonic plates. They still hiss with geothermal activity, especially around the civil parish of Furnas, where hot springs abound. There, locals make traditional Portuguese cozido stew with a twist: They cook it using Furnas’s natural volcanic heat.

Chefs and home cooks begin by gathering their ingredients in a pot—typically some combination of pigs’ ears, pork belly, chicken, taro root, carrots, cabbage, garlic, and morcela (blood sausage). Around 5 a.m., they’ll take their cookware to Furnas’s caldera lake. Everyone has a usual spot staked out.

Once they’ve placed the pots of meat and vegetables in the ground, it takes six to eight hours for the stew to cook by geothermal heat. Chefs don’t actually add water or stock to the pot—the steam forces out the ingredients’ juices, creating a natural sauce. The result is moist and flavorful, with a slight aroma revealing its sulfuric origin.