Instructions

1. Preheat oven to required temperature as indicated on your packages of cake mix (325ºF for Bob’s Red Mill brand).
2. Use shortening to thoroughly grease two 8 inch round cake pans – you’ll want to make sure there are no bare spots. Add about a tablespoon of gluten free flour to each pan and completely coat the greased surface with the flour by rotating and tapping the pan. Feel free to add extra flour if needed – any excess flour can be dumped out or saved for the next batch of cake. Just make sure there are no large clumps of flour, especially in the edges of the pan that would create dents in the cake. Set aside.
3. Follow instructions on the package to prepare the first cake mix batter (I just did one package at a time). For the Bob’s Red Mill cake mix, you’ll want to reference the “white cake variation” instructions. Divide this first batch evenly between the two cake pans. Bake according to package directions. Move on to step 6 while waiting on the cakes to bake and cool but as soon as the first batch of cake comes out of the oven, come back to steps 4 and 5.
4. Once the first batch of cake finishes baking, move the pans to a cooling rack and set a timer for 15 minutes. While the cakes are cooling in the pans, prepare the next package of cake mix and set the batter aside.
5. Once the 15 minute timer elapses, gently jiggle the cake pans until the cake moves around freely. At this point, you can flip them out of the pan and onto the cooling rack without the cake breaking. Wash and completely dry the cake pans and prep again as you did in step 2. Repeat the same process to bake, cool, and remove the cake from the pans.
6.  If you are proficient with piping lettering onto a cake, it may be easier to skip making a stencil and proceed to step 9. However, if you would like a guide for letter placement and size, I found the stencil to be really helpful. Just know that you cannot make an exact transfer of the stencil to the cake - instead, you will trace it onto the frosted cake using a toothpick and the toothpick marks will act as your guide while piping. If you decide you want to make the stencil, you can download the stencil here and print out page 2.
7. Position the printout on a self-healing cutting mat. One with a non-slip bottom is safest. Very carefully use an X-ACTO knife to cut out the letters and discard them. The easiest way to do that without tearing the paper is to make all your vertical cuts first then go back and make the horizontal cuts and other angles with the aim being to avoid putting a lot of pull on a delicate area of the paper. The letters don’t have to be perfectly clean, just clear enough to trace a toothpick through it onto the cake.
   
8. Use scissors to cut the gray oval area of the stencil. Set aside.
9. Gather the ingredients needed to make the vanilla buttercream. In a stand mixer with a whisk attachment, combine the powdered sugar, salt, vanilla, and almond milk on low speed until smooth.
10. Add the dairy free butter one slice at a time until incorporated. Add the shortening then whip at the highest speed for about 10 minutes or until it appears to have doubled in volume. Set aside to use as your cake filling later.
11. Make a second batch of buttercream if you'd like to use it to frost your cake. (Since there's plenty of filling in terms of taste and the outside frosting will be colored so dark that you might not want to eat it, it's cheaper to just use the piping icing on the outside instead of a second batch of buttercream). If you decide to make the second batch of buttercream, divide it into thirds and use the food coloring listed under the piping icing ingredients to color the portions black, blue, and purple. You can add a drop or two of black to the blue and purple buttercreams if you want to darken them a bit. Set aside.
12. Gather ingredients needed to make the piping icing. In a stand mixer with a paddle attachment, cream together the shortening, water, and vanilla extract. Slowly sift in the powdered sugar - you may not use all of it. Continue mixing in the powdered sugar until the frosting is stiff enough to pipe but not dry. (How much powdered sugar you use depends on the type of shortening. My original piping icing recipe calls for the entire bag but I'm not used to working with this new non-hydrogenated shortening I had to switch to and I probably only put in 6 cups of powdered sugar but it was too stiff.)
13. Reserve about 1/4-1/3 C of the icing to pipe the lettering on with. This should give you plenty of icing to practice with if you need to. You can color it if you want but I kept it white. Store it in an airtight container with plastic wrap coating the top of the icing so it doesn't dry out.
14. Portion out about a half cup of the icing to make the moon. Add a drop of black gel food coloring at a time until you achieve a light gray color. Set aside until ready to use, storing it the same way you stored the white icing in step 13.
15. (Skip this step if you decided to make colored buttercream in step 11.) The remainder of the piping icing will be colored black, blue, and purple. You may need to make a second batch of piping icing at this point in order to cover the entire cake. You can get away with a fairly thin layer but having more makes things easier. Separate the icing into thirds and color the first third black. Repeat with the other two portions but color them blue and purple. You can add a drop or two of black to darken those colors if you prefer. Set each of these aside until ready to use, storing them the same way as described in step 13.
16. After the cakes have cooled completely, use a bread knife, cake leveler, or your preferred method to level the cakes.
17. If you’re wrapping the cake board in any sort of decorative foil, do that now (I chose not to do this). Place the cake board centered on the lazy susan and smear a small dollop of the piping icing you made onto the middle of the cake board. Place one of your four cake layers in the middle of the cake board so it’s secured by the icing smear.
18. If you've never stacked and filled a cake before, Wilton has a really good tutorial. I was having a hard time writing the instructions in a way that was clear. If you're familiar with the process, this step should make sense. Fill a piping bag (you don't necessarily need a tip) with the buttercream you made in steps 9-10 (non-colored) and pipe a dam of frosting on top of your first layer. Fill inside the dam with more buttercream and use the angled spatula to spread it evenly. Top with the next layer and repeat until you get to the top (the top won’t need frosting over it). When you get to the very top layer, I recommend placing it leveled side down so you get the clean edges from the cake pan on top. Use the remaining buttercream to fill in any gaps between the layers so you have one solid stack of cake (this is where a piping bag is helpful).
19. Use a small amount of the colored icing/buttercream (blue, black, or purple) to make a very thin layer of frosting all over the cake. Note that this is to be a crumb coat, not the actual finished cake frosting. It's not meant to be even, perfect, or beautiful. A crumb coat is a very thin layer of frosting meant to adhere any loose crumbs to the cake which prevents them from getting into your decorative frosting that will be seen on the outside.
    
20. Use an angled spatula to place a few globs of blue icing onto the top and sides of the cake. Just randomly position them. Drag the angled spatula or an icing smoother around the cake to smooth the globs into streaks. You'll still have a lot of crumbcoat showing and that's fine for now.
    
21. Place globs of purple icing over any areas where you still see crumbcoat. You don't have to hit all of them since we still need to add black but really start filling in the gaps. Streak the purple in the same manner you did the blue.
    
22. Repeat with the black icing but this will be the final layer so be sure no cake or crumb coat is showing at this point and that the colors are distributed to your liking. Smooth it out as best as you can to finish without over-blending the 3 colors. You can finish smoothing it with parchment paper but I've never been good at this method so I skipped it if you couldn't tell ;)
    
23. Squeeze a little white gel food coloring into a small bowl. Dip a small food-safe paint brush (stiffer or angled brushes work best) into the food coloring and drag your finger along the bristles in order to flick the white color onto the cake. (It will look like stars. You can practice this technique on some black frosting smeared onto a scrap piece of parchment paper or other material.) I did a cluster of these white "stars" on one area of the cake in order to make it look kind of like the milky way.
    
24. Now you'll need to get an outline of the moon on the top of the cake using a toothpick. You can free-hand this if you're confident or you can make a quick and easy stencil. To make the stencil, you'll need a standard sized sheet of printer paper, one of the cake pans you used to bake your cake, a pencil, and scissors. Use the bottom of the cake pan to trace a circle onto the paper. This circle is the same diameter as your cake. Now slide the cake pan to the side until the uncovered area of the paper shows the size crescent moon you want. Trace the outside of the cake pan and you'll be left with a crescent shape to cut out on your paper. (You can touch up with your pencil if you'd like the middle thicker, more drastic taper, etc).
    
25. After you've cut out the crescent moon, position it on the top of your cake with the outside edge of the crescent touching the edge of the cake. Once it's positioned where you like it, gently use a toothpick to trace the moon onto your cake. Carefully remove the paper. (You can see in the photos that I did this step and the next one at the same time.)
    
26. (Skip this step if you aren't using a stencil for the lettering.) Place the lettering stencil you made in steps 6-8 on the non-moon area of your cake. After you have it lined up right, trace the letters with a toothpick the same way you traced the moon. Carefully remove the stencil.
    
27. Now you can pipe the design onto the cake. To make the moon, attach a Wilton tip #107 to a piping bag and fill it with the gray piping icing you made in step 14. Pipe the gray icing into the moon shape on your cake - I did swirls and filled in the bare spots with "dots" of the icing.
    
28. To pipe the text, it's easiest to use one bag with a coupler attached so you can switch out tips. Otherwise, go ahead and use 2 bags. Fill the piping bag with the white icing you reserved in step 13. Attach a Wilton tip #2 and write the text "let's go" and "the moon", using the toothpick marks as your guide if you made them. Switch the tip out for Wilton tip #101 to write the word "TWO". If you make a small mistake and your icing is stiff enough, you can generally pick off a letter using a toothpick and try again.
    
29. Once everything is to your liking, insert the candles and it's ready to enjoy!