Blend with an electric mixer on low speed for 1 minute. Stop the machine and scrape down the sides of the bowl. Beat 2 to 3 minutes more until combined. Pour ⅔ of the batter in a greased and floured 12 cup bundt pan.
Mix together filling ingredients. Spread filling over the batter and top with remaining batter Bake for 45-55 minutes until the cake springs back when lightly pressed and is starting to pull away from the sides of the pan.