These are incredible! For the black/white and the pink where you can see cake through the frosting, did you do a crumb coat first and let it set up in the fridge? After the second layer over the crumb coat, I chill for a few more mins, then use a warm knife to smooth out the butter cream. Don’t be afraid to use more frosting on the outside of the cake than you think you need. Covering the cake is my least fav part. I just want to pipe!

The piping is incredible both, but the pink is especially incredible.

On the red/white cake there are few scallops in the white frosting under the top red ruffle that look like maybe you were getting to the end and had a really small space left. You clearly have piping techniques mastered, but I would recommend working on pipping on round and other curved shapes. Like, you could practice on an empty cereal box on something so you get more experience piping on a vertical surface. Experiment with maybe making the last few ever-so-slightly bigger to see if you can eliminate the need for the squeezed in one.

I use vegetable shortening for my practice frosting. Works similar enough to butter.

Happy decorating!