1 BEAT first 4 ingredients at low speed with an electric mixer until blended. Gradually add 1 1/4 cups cola. Increase speed to medium, and beat 2 minutes. Pour into a greased and floured 13- x 9-inch pan.
2 BAKE at 350 degrees for 30 minutes or until a wooden pick inserted in center comes out clean. Cool in pan on a wire rack 10 minutes.
3 COOK butter, remaining 1/2 cup cola soft drink, and cocoa in a large saucepan over medium heat, stirring constantly, until butter melts. (Do not boil.) Remove from heat; stir in powdered sugar and vanilla. Stir in pecans.
4 SPREAD warm frosting over top of warm cake; cool completely on wire rack.