Preheat oven to 170 C. Grease a baking dish with butter.
Peel and cut the pears in half. Remove the core and put the halves in the dish. Vanilla pod cut along. Mix vanilla seeds with sugar and sprinkle pears on them.
Cut the vanilla into 4 parts and put them in different parts of the dish. Cut the remaining butter into small squares and put them on the pears on top. Sprinkle with nuts.
Bake for about 45 minutes, the time also depends on the size of the pears and their degree of maturity. Periodically check the pears and pour them on top of the juice that stands out.