Try a square cake, stacked, then cut diagonally... then carve slightly to make the ramp realistict.( The cake will be on its side). HTH
Oh yeah! Now you've said it, it's obvious!
Sometimes, I just can't see things for looking!!!!!
I did one similar and used a double quarter sheet. There is no way around losing cake when you have to carve the ramp. I didnt' carve out a real deep "U" shape in order to save the servings. Mine is all butter cream too.
Fantastic cake, ddaigle! Thank you x
the cake you cut out to reveal the rounded ramp can be cut in half and restacked onto each end to build up the height of the ramp
just match up the smooth lines --
and recut the scoop
Depending on the size you need, you could also try a 13x9 as the base and loaf cakes for the sides. Less cake to trim from the middle.