Preheat oven to 350°F. Prepare 2 8 in. pans with vegetable pan spray.

In small bowl, combine flour, cocoa powder, baking soda and salt.

In microwave-safe container, combine 1 cup chocolate chips and butter. Melt on full power in 30-second intervals, stirring between each, until chocolate is fully melted and smooth. Let cool slightly.

In large bowl, combine butter mixture and sugar. Beat on medium speed with an electric mixer until well combined. Add eggs, one at a time, beating well between each addition. Add vanilla. Add flour mixture alternately with water in 3 additions; beat until well-combined.

Bake 50-55 minutes or until a toothpick inserted into the center comes out clean. Remove to cooling grid. Cool 10 minutes in pan before removing. Cool completely.

Level cakes using a knife or cake leveler. In microwave safe container, melt remaining 1 cup chocolate chips on full power in 30-second intervals, stirring between each, until melted. Divide evenly over both cake layers and spread into a thin layer. Refrigerate layers 15-20 minutes or until chocolate has hardened.

To stack cake, place one layer chocolate side up on serving plate or cake board. Fill with desired icing. Place second layer on top, again with chocolate side up. Decorate as desired.