To pipe the Christmas tree, fit a piping bag with tip #1M, and fill with buttercream.
If you need to, practice your piping first on a piece of wax paper. Then you can scrape the buttercream back into the bowl and use it again. There are only two styles you need to master for today’s cake.
First, practice piping a “shell”. A shell involves first pushing the piping tip forward slightly, and then pulling it back in the opposite direction. This will create a rounded look for the bottom of the branches. You’ll be piping this shape in a vertical line, from the bottom of the cake, upwards.
Then, practice the “swoops” shown in the next image. This is sort of like a shell, but with a little swoop off to the side, before piping upwards. I used this shape for the outer branches on my cake, to give it a prettier shape.
Start at the bottom of the cake, and pipe a vertical shell in the center, from the bottom edge, up to the first horizontal line on your template.
Then pipe 1-2 more shells on either side of the middle one, to start filling in your template. To finish the bottom row, pipe a swoopy shell on each side. On the left of your Christmas tree, swoop from the left towards the right. On the right side of your tree, swoop from the right towards the left.
Now pipe the branches on the 2nd, 3rd and 4th sections, always working your way from the middle to the edge. The top branch of the tree should be the last branch you pipe.
4-Layer Cake Option. Note that on my cake, which is a 7-inch tall, 4-layer cake, I have 4 sections of branches. The bottom section has 7 piped branches, the next has 5 branches, the next has 4 branches, and the top has 2 branches.
3-Layer Cake Option. For a shorter 3-layer cake, you may only need 3 sections of branches, or you could also do 4 shorter sections. This will mean that you’ll be piping fewer branches. Your bottom section might only have 5 branches, the middle section might only have 3-4 branches, and the top section will have 2 branches.