Preheat your oven to 350 degrees and grease 3 9 inch cake pans with non-stick cooking spray.

Cream butter, shortening, and sugar until light and fluffy.

Add eggs, one at a time, mixing throughly in between each addition.

Mix in vanilla.

In a separate bowl combine flour, baking powder and salt and mix to combine.

Add ⅓ of the flour to the butter/egg mixture, mixing on low.

Mixing just enough to combine, add ⅓ of the buttermilk.

Continue until all of the flour and buttermilk has been incorporated, again mixing until just combined (do not over mix!)

Evenly distribute cake batter into pans and bake for 25-30 minutes, or until a toothpick or cake tester inserted in the center comes out clean. Remove from oven and allow to cool slightly in cake pans for about 5 minutes, then cool completely on a wire rack.

To make the Italian Meringue combine 1 cup of sugar and water in a small sauce pan.

Heat sugar and water on medium until boiling (you want large bubbles).

In the bowl of your electric mixer, beat egg whites and sugar until frothy.

Increase your mixer speed to high and beat egg whites until hard peaks form.

Reduce mixer speed to low and slowly and carefully pour into egg whites.

Slowly increase the mixer speed again and beat until the mixture is no longer hot or warm and is fluffy. (mixture needs to be as close to room temperature as possible before adding butter).

With the mixer set at medium speed, slowly add butter pieces. Mix until smooth.

Separate buttercream into 3 bowls, and color with your preferred frosting colors.

Fill each layer with buttercream and stack cake.

Frost assembled cake.