Preheat the oven to 400 degrees . Arrange the pears, cored side up, in a 9-by-13-inch baking dish. In a small bowl, stir together the sugar and cinnamon. Squeeze the lemon over the pears and sprinkle with the cinnamon sugar. Pour 1/4 cup water into the baking dish and cover with foil. Bake until the pears are tender but still hold their shape, about 30 minutes. Add 2 tablespoons water to the baking dish and set aside to cool.
Cut the pears into small cubes and toss with the baking liquid. Spoon 1/4 cup chopped pears into each of 4 parfait glasses. Top with 1 tablespoon granola, 2 tablespoons yogurt and about 1 teaspoon maple syrup. Repeat the layering.