Preheat oven to 350°.
Beat margarine and 1/3 cup brown sugar at medium speed of a mixer until well-blended. Add eggs, 1 at a time, beating well after each addition. Add milk and lemon rind; beat well. Combine flour and next 4 ingredients (flour through salt); add to creamed mixture, and beat well. Stir in chopped apple.
Spoon batter into a 9-inch round cake pan coated with cooking spray. Bake at 350° for 28 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 5 minutes; remove from pan. Let cool completely on a wire rack.
Preheat oven to 475°.
Combine remaining 1/3 cup brown sugar, water, and cinnamon in a 2-cup glass measure; stir well. Microwave at high 30 seconds or until sugar dissolves. Combine nectarines and brown sugar mixture; toss well. Arrange nectarines, cut sides down, in a 13- x 9-inch baking dish. Bake at 475° for 15 minutes or until tender. Turn nectarines over; sprinkle with turbinado sugar. Bake an additional 5 minutes. Serve with cake. Garnish with cinnamon sticks, if desired.
Pear Variation: Substitute 6 small, firm Bosc pears, cored and quartered
(2 1/4 pounds), for nectarines, if desired.