I'd like to make a slab cake with different coloured sides than the top (like the one in the picture that I attached). Is there an easy way to do this? When I ice a cake in buttercream, I always have some of the icing on the sides come up onto the top and vice versa. Should I be icing the top first or the sides? Any advice is appreciated. Thanks.
I do the whole cake first, smooth it, and then do a second layer on the top, so the top ends up with two layers of frosting. After smoothing the top (again), I will scrape the sides once more for any excess from the top coat. You will see the two shades on the side (at the top), but your border will hide that.
You could also do a frozen buttercream transfer (FBCT). Outline the size of your cake onto a piece of wax paper, smooth the buttercream out, freeze it and then lay on top of your cake. There are (better) instructions for the FBCT here on CC, should you go that route.
Yep, same here, I add a thin layer of the top color on top of the icing that's already there. I try to get close enough to the edge that the border will cover the line between the colors.
Thank you guys! I'll try that! :)