Preheat the oven to 350°F (180°C.) Dot centre of each apple with 1/2 tsp (2 mL) butter. Combine brown sugar with cinnamon. Sprinkle evenly over each apple. Sprinkle granola evenly overtop.
Place apples, cut side up, in 8-inch (2 L) square baking dish. Drizzle water over and around apples. Cover with foil. Bake in the centre of the oven for 40 to 45 min, or until apples are tender.
Serve warm topped with yogourt.