Prepare Icing 24 hours ahead of time if possible

Cream together margarine, shortening, and butter, and vanilla

Add powdered sugar, then Peanut Butter. Mix 3 to 5 minutes on medium speed

If you are making it ahead of time, cover it with plastic wrap and leave it at room temperature

For the cake, separate the wet and dry ingredients into two different bowls

Mix the wet ingredients with a whisk, then slowly add the dry ingredients

If you are using a mixer blend on a slow speed

Once the butter is thoroughly incorporated, divide evenly and pour into two 9" pans that are greased with non-stick release spray and dusted with flour.

Bake at 350° for 22-25 minutes

Once cakes have cooled completely, cut layers in half and put the icing in between all layers

I made this a three-layer cake, but you can make it a four-layer cake if you want

Ice the outside of the cake with a thin layer of icing first and place in the refrigerator for about 20 minutes to set the crumbs

Then ice the cake with a finishing layer of icing

Place Peanut Butter cups on the cake for decoration if desired