Copycat McCain Cake (cake portion also known as Better Than a Bakery Chocolate Cake)
1 1/2 c. water
2 c. sugar
3/4 c. butter
2 eggs, slightly beaten
1 tsp. vanilla
2 c. flour (all whole wheat works, but it is slightly heavier)
1/2 c. cocoa
2 tsp. baking soda
1/2 tsp. salt
Cream butter in bowl. Bring water to boil, add to butter, stir until melted. Add sugar, stir until dissolved. Add eggs & vanilla, mix well. Combine dry ingredients. Add to butter mixture, mix well. Batter will be VERY thin. Pour into greased & floured 9" x 13" pans (or you can reuse 2 empty McCain pans).
Bake at 350*F for 30-35 minutes. When cool, frost with "Secret" Frosting (recipe follows) by piping it onto the top of your cake(s) with a star piping tip. Keep the frosting cool, use a small amount in your decorating bag at a time and work quickly. If it gets too warm, refrigerate it for a few minutes. Sprinkle with chocolate sprinkles. Cover, chill and/or freeze when done. Best eaten partially thawed the next day. You will have some left over frosting. I think that you will know what to do with that! 
"Secret" Frosting (also known as French Silk Pie filling)
1 c. butter
1 1/2 c. sugar
2 tsp. vanilla
Cream well.
4 x 1oz (4 x 28g) unsweetened Baker's Chocolate squares, melted
2 Tbsp. cocoa
Add & mix.
4 eggs
Beat eggs in one at a time, 5 minutes each at med. speed. (I cut it down some, but this is done to give it lift)
Chill 4 hours if using as pie filling. Will fill 2 pies. If using for pie, top with whipped cream, serve in small slices. It is VERY rich.
The resulting cake is way better and more flavorful than the bought version! I can't take full credit for creating this recipe, but I did put the two together to solve the mystery! My daughter could not have the bought version due to the chemicals in it, so I was on the hunt for the ultimate cake recipe. I could not find it online, so I did some experimenting. You are the first ones to get the recipe in this form.
I knew that you would appreciate it.
I would like to try this recipe out with a Crazy Cake recipe and Suzanne's moist Chocolate Cake recipe. I also am planning to try this with a melted white chocolate (& no cocoa) in the filling to make a white frosting, and try both of these frostings on both white and chocolate cakes. I know that this company also does a marble cake with chocolate frosting. I would like to try to make a mocha version too. I LOVE mocha anything! As I feel creative, these are the variations that I want to do.
ENJOY!