HEAT oven to 350 degrees F. Spray a 12-cup fluted pan with flour no-stick cooking spray. Combine all cake ingredients in large bowl at low speed until moistened; beat 2 minutes at medium speed. Pour batter into prepared pan.
BAKE 45 to 55 minutes or until toothpick inserted in center comes out clean. Cool in pan 25 minutes; invert onto serving plate. Cool completely.
HEAT white baking chips and 1 tablespoon oil in small saucepan over very low heat until chips are melted; stir until smooth. Cool slightly. In another saucepan over low heat, heat chocolate chips and 1 teaspoon oil until chips are melted; stir until smooth. Cool slightly. Drizzle cake with white chocolate, then with dark chocolate.
High Altitude (above 3500 ft.):
SEE package for directions.