I wasn't originally planning on creating a tutorial for this cake, so I didn't take many pictures during the process (sorry!), but I will explain to the best of my ability.
There were a few non-edible items that I bought for this cake: the glass globe (floral bowl) from the Dollar Tree, which is about 6 inches in diameter at its widest point and 4.5 inches in diameter at the base; an inexpensive gold plated tiara from Amazon; an Olaf figurine from the Dollar Tree; and Elsa and Anna Christmas ornaments from Wal-Mart. I also picked up two tutus from the Dollar Tree that I glued around the base of my cake board.
I used an eight-inch base tier and a six-inch top tier of cake on a ten-inch cake board. I covered each tier with a layer of white chocolate ganache and white fondant, and then I airbrushed each tier before stacking them. The colors that I chose to use were Americolor sky blue, mixed with a little bit of leaf green and a few drops of silver, which gave it a kind of shimmery effect. My goal was to make the color dark at the top, and then gradually get lighter so that it was white at the very bottom, so I sprayed the most color around the top of the cake and then worked my way down. After I finished painting it, I brushed on some white luster dust. You can't really tell from the pictures, but the cake is sparkly (like new-fallen snow!). You can kind of see the sparkles in the picture below, but for some reason, the luster dust doesn't really photograph well.
After painting the tiers, I stacked them and then added the snowy borders. Luckily, I did take a couple of pictures of this process. I started by taking a 12x12 inch piece of scrapbook paper (cardstock) and I traced the circumference of my 8-inch cake pan. Then I drew some smooth bumps around it and cut it out. I also cut out the center so that the fondant in the middle wouldn't get wasted.
Jessica Harris created a great tutorial for her "wax paper transfer method" which I use almost every time I make a cake. All you need to do is spread a thin layer of shortening (Crisco) onto a piece of wax paper (with a brush, your hand, or a paper towel). Then roll your fondant out on top of it. Lay your template down on top of your fondant.
Next, use a sharp knife to cut around the edge of your template and remove all of the excess fondant. Your fondant design should remain stuck to the wax paper. If your knife did not penetrate through the wax paper in the center, go around it once more so that you can remove the center circle of wax paper. Then brush some edible glue, piping gel, or a sugar/water mixture onto your design:
Cut a slit in one side so that you can open your circle, and then wrap your design (wax paper and all) around the top of the eight-inch tier of your cake, so that it meets the bottom edge of the six-inch tier.
After I added the snow to my cake, I pressed the open end of the glass globe firmly onto my top tier so that I could see the outline of where I wanted to put my trees and the Olaf figurine. Then I made my trees.
Unfortunately, I didn't take any pictures during the tree-making process, but the good news is that I have already made trees for a previous tutorial, so I will cut and paste the instructions into this tutorial. The difference is that the trees for this cake were made out of white fondant, not green.
To make the trees, I rolled a piece of fondant into a cone shape, poked a bamboo skewer up through the bottom, and made several triangular cuts in the fondant with a small pair of scissors.
Once all of the cuts had been made, I curled the ends up with my thumb.
When I made the trees for this Frozen cake, I didn't curl the tips up quite as much, because I wanted them to look like they were being weighed down with ice and snow. To make the flat-backed trees around the base of each tier, I followed this same procedure, but then I removed the skewer and cut each tree in half vertically. I lightly misted each tree with my airbrush, using the same color mixture as before. Then I attached the trees to the cake.
For the trees under the dome, I just poked the skewers down into the top of the cake. Then I put a little bit of piping gel on Olaf's feet and pressed him down into the fondant in front of the trees. I added a few little snowballs because I felt like it was missing something, and then I dusted the top with luster dust. (You can see how hard I pressed into the fondant with the globe earlier!) I left the globe off of the cake until morning, so that the trees would have time to dry/harden.
Next, I attached the flat-back trees to the base of the cake with some piping gel, and then dusted the whole cake (again) with luster dust... Can you tell that I LOVE glitter? :-)
After all of the trees were attached, I cut out the letters of Lily's name and the number 4 using the Funky Alphabet Tappit Cutters. Before applying them to the cake, I sprayed the bottom of each letter/number with a light mist of color. I gave them a few minutes to dry, and then I attached them to the cake with piping gel.
I cut out a few snowflakes with my snowflake cutters. Then I let them dry for about ten minutes before attaching them with piping gel, because they are fairly delicate. I attached one under Lily's name, and then made a few more to put around the back of the cake. I also decided to use my clay extruder to make a cylindrical border around the base of both tiers, just to cover up some little gaps.
After I added the border, I stuck the characters to the cake with some piping gel. I ended up pressing them into the cake a little bit, just to help them stay in place better.
The last piece I worked on was the topper. Since the open side of the globe was down, the flat bottom of the globe was on top. In order to make it look more rounded, I took a handful of fondant and rolled it into a ball, then I flattened it out a little bit and pushed it onto the flat part of the globe. Then I pulled down some of the edges to make them uneven, like dripping snow. I left the fondant fairly thick on top, since I knew that I wanted to push the crown into it for stability.
That brings me to another point... The crown, though it's the perfect size for this cake topper, is relatively brittle. When I received it, it was broken into two pieces (near the center of the base) and the comb part had already broken off. The good news is that I was able to push it fairly deep into the fondant, which held it together, and I think it worked out better without having the comb attached. (You can see in the picture how thick the fondant is on top.)
So, that's it! I finally got to make a snow globe cake! Oh, and I forgot to mention that I dusted the whole cake one more time with luster dust. What a surprise. ;-)
And here is the BEST photo that I took... My sweet little birthday girl!