The dish comes from the town of Elbasan in central Albania, which is why some menus call it 'tavë Elbasani'. Families have been making it for generations. Most have their own small differences - a bit more lemon, a leaf of mint, a sprinkle of paprika on top - but the basic idea is the same all over Albania.
Yogurt is a really important part of Albanian cooking. Almost every kitchen has a jar in the fridge. Some grandmothers still make their own at home, letting fresh milk turn slowly into thick, tangy yogurt overnight in a warm corner of the kitchen.
Tavë kosi is usually shared. The clay pot is put in the middle of the table and everyone helps themselves. It goes well with bread or rice, and a fresh salad on the side. On Sundays many families eat it as a proper sit-down lunch, with everyone home.
What makes it special is the way the yogurt changes in the oven. Cold yogurt is white and runny. Baked yogurt becomes thick, golden, slightly puffed up, and a bit like a soft cheese soufflé. That trick - turning something simple into something amazing by baking - is the heart of a lot of Albanian cooking.