The ancient Viking kitchen featured a built-in outdoor pizza oven known as a 'bakarstein'. These ovens were made of stone and were used to bake a variety of bread, including flatbreads similar to pizzas. The Vikings enjoyed toppings such as fish, meat, and herbs on their flatbreads, creating a hearty and satisfying dish. The 'bakarstein' was an essential part of the Viking kitchen, allowing them to cook their pizzas in an outdoor setting, adding a rustic and smoky flavor to the dish.