Melt the white chocolate and cream together at very low heat, set aside.
Beat the butter until light and fluffy, add the sugar a cup at a time and beat well. Drizzle in the white chocolate and beat until combined.
Separate the buttercream into 2 equal batches and color two of the batches with blue and green food coloring in different shades of the scales.
For the Cake
Butter and flour 3 six-inch cake pans. Preheat oven to 350F
Sift the dry ingredients together in a large bowl.
Mix the wet ingredients (including the sugar) together in a medium bowl.
Add the wet to the dry and mix until just combined.
Divide the mixture into 3 6″ cake pans that have been buttered and floured.
Bake at 350 for about 25-30 minutes or until the centers are springy to the touch.
For the Assembly
Pipe rings of the green and blue buttercream onto the first layer then cover with the second layer. Repeat step.
Cover cake in a thin layer of buttercream and give a rough smooth.
Place green and blue buttercream in a piping bag fitted with a large round tip. Pipe the petals by swiping up with the tip.
If you’re not using 6-inch pans, double the recipe for 8-inch pans or triple the recipe for 9-inch pans.
Measure your flour correctly! Adding too much flour to the recipe is the most common mistake. The best, and easiest way to measure flour is by using a scale. If you don't have one then fluff your flour with a spoon, sprinkle it into your measuring cup, and use a knife to level it off.
If you see little clumps of butter after you mix the wet ingredients don’t panic, it all works out by the time you mix in the dry ingredients. You can even use melted butter and warm the milk and sour cream up a bit if you like.
You can substitute whole milk yogurt for the sour cream if desired, I do it all the time and can’t really tell the difference.
To get FLAT layers that are moist inside and out try using cake strips! You can buy a set on theshop page or make your own from foil and paper towels at home. I made a wholeblog post on it so check it out if you’re interested!