Preheat oven to 350. Lightly grease and flour 12 cup bundt pan.
Beat all ingredients together (except chopped chocolate) in a large bowl on low speed until just blended. Beat on medium speed until well blended. Stir in chocolate chunks. Pour into prepared pan
Bake for 50-60 minutes until toothpick comes out clean from center. Cool in pan for 10 minutes on wire rack and then loosen edges with a knife. Flip onto wire rack and let cool. Dust with powdered sugar if desired.