Secret Chocolate Cake from Simply in Season by Mary Beth Lind and Cathleen HockmanWert

2 c beets (cooked, peeled, and chopped)
1/2 c applesauce
Puree in blender until smooth, set aside

1 1/2 cup sugar
1/2 cup oil
1/2 cup plain yogurt
3 eggs
Combine in large mixing bowl. Beat with electric mixer 2 minutes

1/2 cup cocoa (sifted)
1 1/2 tsp vanilla
Add along with puree beets: beat another 90 seconds.

1 1/2 c flour
1c whole wheat flour
1 1/2 tsp baking soda
1/2 tsp salt
1 tsp ground cinnamon (optional)
Gradually sift into the batter, mixing it win with a spoon but stirring only until blended.

1/2 c chocolate chips and/or nuts (chopped)
Stir in. Pour into greased 9 x 13 inch/ 3.5 L baking pan. Bake in preheated oven at 350F (180C) until knife inserted in center comes out clean, 40-50 min. To bake in a bundt pan, pour half of batter into greased pan, sprinkle chocolate ships evenly on top, then add remaining batter.

Modified Version
For those of you that have tasted and enjoyed the modified version (albeit, less healthier), here are the following modifications:
1 a little more apple sauce, all made straight from apples, no sugar added (approx 1/4 cup)
2 add a extra heaping 1/2 c sugar
3 a healthy 1/4 c more of oil (or butter)
4 a bit less than 1/2 c extra of cocoa
5 All white flour instead of whole wheat, or just less whole wheat.