Maybe it’s because I use too many strokes with the knife. The Food Network says that the fewer strokes you use, the smoother your layers will be. And suggests using toothpicks to help guide your cutting. Bon Apetit even suggests using a ruler as your guide!
However, I found a bit of advice that has worked like a charm and doesn’t require an elaborate set up of toothpicks. All you do is get some dental floss — yep, I said dental floss — and use it to slice through the cake. I recommend using one of the unflavored varieties, preferably unwaxed, so that you don’t add in extra, unwanted flavors to your cake.
How To Use Dental Floss to Slice a Cake Layer
Usually, I’ll create a guideline with a knife, maybe even start the cutting a bit in a few places. Then I’ll cut off a piece of dental floss that is long enough to wrap around the edge of the cake layer and a bit more to hold on to. I wrap the floss around the cake, making sure it fits nicely into the guide grooves I created, cross the ends and slowly pull it through. It’s kind of like you’re tying a knot and pulling it tight. This pulls the dental floss through the cake, cutting it into two layers.
Then all you have to do is separate the layers so you can add the filling. But that’s another post.
Want to see this idea in action? You can watch a demo of this technqiue on YouTube courtesy of Food & Wine.