Moist Chocolate Cake with Chocolate Fudge Frosting

I made some 50's food for a book club recently and I decided to make this cake for the main dessert. (I thought that being homemade with sprinkles on top made it Fifties enough.:)) I really love this cake because it is so moist and chocolatey with just a hint of cinnamon. Awesome. It is actually pretty much a Texas Sheet Cake made in a 9x13 pan, which just makes it thicker and moister. Win win! And can I just say I don't think I've ever had such a great reaction to a cake from my whole family. They loved it! Oh and the frosting! The frosting! It is fabulous!

Moist Chocolate Cake with Chocolate Fudge Frosting

Cake:
2 cups flour
2 cups sugar
1 teaspoon baking soda
3/4 teaspoon salt
1/2 teaspoon cinnamon
1/2 cup butter
1/2 cup applesauce
1/3 cup cocoa powder
1 cup water
1/2 cup buttermilk
2 eggs
2 teaspoons vanilla

Frosting:
1/2 cup butter
1/4 cup cocoa powder
1/4 cup milk
4 cups powdered sugar
1 teaspoon vanillla

Preheat oven to 375. In a large mixing bowl whisk together: flour, sugar, baking soda, salt, and cinnamon; set aside.

Melt butter in a saucepan then stir in applesauce, cocoa powder, and water and bring mixture to a boil, whisking constan. Pour hot butter mixture into flour mixture and stir. Add in buttermilk, eggs, and vanilla and whisk mixture until well combined. Pour mixture into a greased 9x13 baking dish and bake for 25-28 minutes or until toothpick inserted in center comes out with a few moist crumbs. Prepare frosting during last 5 minutes of baking.

For frosting: in a medium saucepan combine butter and cocoa powder and bring mixture just to a boil, stirring constantly to break up cocoa powder. Remove from heat. Pour mixture into a stand mixer (or use a hand mixer), add milk, powdered sugar, and vanilla and beat on low speed until well blended. Immediately spread over hot cake before frosting begins to cool. Also, if using, add sprinkles quickly before frosting sets.