I did a two layer fondant, so I could cut out of windows and have white under the red. Using an Exacto Knive, it leaves rough edges, I tried to smooth them, very difficult while on a cake. I know I've seen nice cuts "Post-Cake" application. PIzza cutter wouldn't work in such a tiny application...
Cindy, first, make sure you always use a brand new exacto blade. I have found that greasing it with shortening helps. Clean off the accumulated sugar as you go and reapply shortening. good luck!
Let the fondant rest on the cake for a few minutes -- especially if it was really warm and soft when it was applied. If it feels like it's dragging, stop cutting and wait a few more minutes.
Also, you can try not cutting all the way through on the first slice. Make several shallow cuts instead.
PME Cutting Wheels
Thank you - I have another one to do tonight...Brand New Knife in hand. I will try the suggestions...and get a PME Wheel cutter..goodie one more toy to accumulate!