Preheat oven to 350°F.
Prep four 6in. (can bake in batches) cake pans by greasing with vegetable oil and lining the bottoms with parchment paper.
Sift together flour, sugar, baking soda, salt, baking powder, and cocoa in a medium bowl and stir to mix.
In a large bowl or stand mixer fitted with a whisk attachment, mix together oil, buttermilk, eggs, food coloring, vinegar, and vanilla.
Slowly mix dry ingredients into the wet ingredients just until combined.
Add 1¼ cups of batter to each pan and bake for about 30 minutes until toothpick comes clean from center.
Remove cakes from the oven and run a knife around the edge to separate from the pan, flip out onto a plate then re-invert onto a cooling rack, rounded-sides up and allow to cool completely.
Slice the rounded top off of the cakes so they're nice and flat.
In a large bowl or stand mixer fitted with a paddle attachment, beat cream cheese and butter until smooth, gradually beat in powdered' sugar followed by vanilla and heavy cream and beat until light and fluffy, about 5 minutes.
Place one layer on a cake board on a cake stand, you can use parchment or wax paper along the edges to prevent the frosting from getting everywhere.
Use a frosting spatula to spread out about a ¼-inch thick layer of frosting, add the next layer and repeat until layers are done.
Use the spatula to spread a thin crumb coat around the sides of the cake, let set or chill for 20-30 minutes.
Using a decorator tool or frosting bag fitted with a large star tip, make roses by starting in the center and working your way out and around until your roses are the size you want them to be. Do this all over your cake.
Cake best within 24 hours.