1. Preheat oven to 350F.
2. Lightly spray nonstick cooking spray on 2 jelly roll pans then line with waxed paper.
3. Lightly spray waxed paper with nonstick cooking spray.
4. In a large mixing bowl combine cake mix, pudding mix, milk and eggs.
5. Spread the batter evenly as possible into the jelly roll pans. The batter will be spread thin.
6. Bake in 350F oven for 13 minutes or until toothpick inserted comes out clean.
7. Let cakes cool for about 5 minutes.
8. Place a large cutting board over 1 of the cakes then flip and remove pan.
9. Carefully remove the waxed paper from the cake.
10. This is your bottom cake layer.

For the Frosting

1. In a small sauce pan whisk flour and milk together until smooth.
2. Bring milk to a boil and stir for 2 minutes.
3. Remove from heat and allow to cool to room temperature.
4. In a stand mixer mix together the butter, coconut oil, vanilla and sugar until fluffy.
5. Add the milk flour mixture and beat on high for 10 minutes or until fluffy.

Assemble Cake

1. Spread frosting evenly on the bottom layer cake.
2. Remove second cake like the first cake with another cutting board or wire rack and gently peel of waxed paper.
3. Place cake directly on top of the frosting.
4. Trim off thin edges.
5. Slice into bars.

Sprinkle powdered sugar on top before serving.