Cake: Preheat the oven to 350°F. Spritz a square 8x8 baking pan and an 8-inch round cake pan with baking spray or butter and flour.
In a medium bowl use a whisk to sift together the flour, sugar, cocoa, baking soda and salt.
In a separate medium bowl, whisk together the buttermilk, vegetable oil, food coloring, vinegar, vanilla and eggs until fully combined.
Using an electric mixer on medium speed add the wet ingredients gradually into the sifted dry ingredients beating just until combined.
Divide the cake batter evenly between the prepared pans.
Bake for 25-30 minutes or until the cake springs back when gently touched or a toothpick inserted into the center comes back clean. Do not over bake. Cool for 20 minutes in the pans then carefully remove from the pan to a cooling rack to cool completely.
Cream Cheese Frosting: In a medium-size mixing bowl using an electric mixer on medium-high speed to cream together the cream cheese, butter, vanilla and salt. Lower the speed of the mixer and gradually add the powdered sugar. Whip for 2 minutes or until smooth and creamy.
Assemble: Once the cakes have cooled use a sharp knife to cut the round cake in half to create two equal half circles.
On a large platter or cake stand, place the square cake offset in the center with one corner pointing down. Use cream cheese frosting to attach the two halves to the top of the square cake to create the top rounds and the heart shape.
Frost the entire cake with a thin coat of cream cheese frosting to create a crumb coat.
Smooth the remaining frosting onto the cake and decorate as desired. Store chilled.