PREPARATION:

1. Preheat oven to 350°F. Grease 9-inch round cake pan. Reserve 3/4 cup cake mix; set aside.
2. Pour remaining cake mix into large bowl. Add eggs, water, oil and cinnamon; beat with electric mixer at medium speed 2 minutes. Remove 1/2 cup batter; reserve for another use.* Spread remaining batter in prepared pan; sprinkle with 1/2 cup semisweet chocolate chips.

   *If desired, extra batter can be used for cupcakes: Pour batter into two foil or paper cupcake liners placed on baking sheet; bake at 350°F 20 to 25 minutes or until toothpick inserted into centers comes out clean.

3. Combine reserved cake mix and brown sugar in medium bowl. Stir in butter and remaining 1/2 cup semisweet chocolate chips; mix well. Sprinkle mixture over batter in pan.
4. Bake 35 to 40 minutes or until toothpick inserted into center comes out clean and cake springs back when lightly touched. Cool cake in pan on wire rack 10 minutes; remove from pan and cool completely on wire rack.
5. Place white chocolate chips in resealable food storage bag; seal bag. Microwave on HIGH 10 seconds and knead bag gently. Repeat until chips are melted. Cut off 1/4 inch from corner of bag with scissors; drizzle chocolate over cake. Let glaze set before cutting cake into wedges.