Preheat your oven to 350°F (175°C).

In a large bowl, whisk together flour and sugar.

In a saucepan, melt butter with cocoa and water. Bring to a boil, then remove from heat.

Pour the hot mixture over the dry ingredients and mix well.

Add buttermilk, eggs, baking soda, and vanilla. Mix until smooth.

Grease a 9x13 inch baking pan.

Pour the batter into the prepared pan.

Bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.

Allow the cake to cool completely in the pan.

In a saucepan, combine drained pineapple, sugar, and cornstarch.

Cook over medium heat, stirring constantly until thickened.

Remove from heat and let it cool completely.

Once the cake has cooled, spread the pineapple topping evenly over the surface.

Slice 2-3 ripe bananas and arrange them on top of the pineapple layer.

In a large bowl, beat cream cheese and butter until smooth.

Add peanut butter and mix well.

Gradually add powdered sugar, milk, and vanilla. Beat until creamy and smooth.

Spread the peanut butter cream cheese frosting over the banana and pineapple layers.

For an extra touch, sprinkle chopped peanuts on top.

Slice and serve your Elvis Presley sheet cake.