In large bowl, using electric mixer, on medium speed, beat together cream cheese and sugar until smooth. Beat in egg and vanilla on low speed. Beat in sour cream just until blended. Set aside.

Slice top off apples, about quarter way down; discard tops. Using spoon, scoop out and discard each core. Scoop out apple flesh, leaving a 1/4-inch (5 mm) shell. Reserve apple pieces.

In 13- x 9-inch (3 L) baking pan, place apple shells. Pour in cheesecake filling to 2/3 full. Bake in 350°F (180°C) oven for 50 to 55 minutes, until filling is firm. Let cool. (Filling will sink.)

Finely chop reserved apple pieces; measure out about 2-1/2 cups (625 mL). In large skillet, over medium heat, melt butter. Add chopped apples and 1/4 cup (50 mL) of the maple syrup. Cook, stirring for 5 minutes until apples are tender. Remove to small bowl; let cool.

To serve, top each apple with about 1/4 cup (50 mL) of the maple apples. Dollop with whipped cream, if using. Drizzle with remaining maple syrup.