Core apples, but not all the way to the bottom. Peel 1/3 of the way down from the stem end.
Mix pecans and cinnamon, fill apples half-way, top with a piece of butter, and then add more pecans to fill the apples.
Mix marmalade and water. Arrange apples in a baking dish and pour over marmalade.
Bake in a preheated 400 degree oven for 20 to 30 minutes, spooning sauce over apples 2 to 3 times during baking, until apples are tender when pierced but still keep their shape.
Serve at room temperature or chilled. Syrup thickens upon cooling and chilling. Makes 8 servings.