R.J.
These are the kinds of cakes I make :D ((This year I made "mini" cakes for my kiddo's bday -the "minions" from Despicable Me. But I usually make big 3d cakes. Like volcanos, jupiter, a fender strat, etc.))
Probably the single BIGGEST piece of advice I can give you is three fold:
1) Start at LEAST 3 days in advance (and yes, you will need room in your fridge or freezer for that long. ((I'd estimate you're looking at about 12 hours worth of work for a single person, and it's not something you want to do all in one day. So bake the cake on day 1. Cool. Initial frost. Stick in the fridge. Day 2 start on initial round of decorating - this is when I get the fondant layers made and on an start working on any modeling chocolate. Day 3 finishing touches... which always take soooo much longer than I think they will. Day 4 = party. Yes, you can do it all in one day or in two. It's not worth the stress IMHO, and it's nice to have the time to run to the store for whatever was forgotten))
2) Use CORN OIL for the oil in the cake itself. Corn oil will keep it moist (even if uncovered) for about a week. Covered, it will stay moist for about 10 days. As opposed to regular cooking oil which will only keep it moist for about 48 hours.
3) Make your own buttercream (recipe follows). The amount of buttercream needed for a 2 tier cake will cost you about 30-50 dollars if you buy it. Making it will cost you about 6-10.
Okay... so here is how I would do it if I were doing it:
Supplies: (beyond average things like butter knife, corn oil, eggs, glass bowls, etc.)
- Foiled cardboard "thin" for in between the two layers (allows you to cut the top layer), with a SMALL circle cut in the center (for straw or dowel to skewer through).
- Foiled cardboard "thick" for carrying the cake around on
- Bubble Tea Straws (works better than dowels for "smaller" cakes (up to 3-5 layers), and can be cut to the right height with scissors... the giant thick straws -or dowels- placed in the bottom layer are what allows the upper layer to actually SIT on the bottom layer without crushing it
- "Real" cake pans (these pans are at least 2" deep, often 3" deep. I prefer the kind with insertable bottoms, but others prefer springform). You only really "need" one of each shape, but more mean you have to do fewer batches of baking. ((You can use ordinary cake pans, but it makes it harder... because you have thin layers that don't stack as easily))
- Parchment paper (for going in the bottom of each pan so the cake doesn't stick)
- Toothpicks (for testing if the center is baked through
- Long metal spatula (looks like a ruler with a handle and rounded end, thin, and made of metal, it's used for icing and for slicing each layer in half to frost it.
- Bread knife (for slicing off the rounded domes)
- Icing (for in between each layer, and for the surface of each cake - without icing, the fondant doesn't stick to the cake)
- Fondant (I buy my fondant, because I'm lazy. Fondant comes in 2 basic types: White and Chocolate. White fondant takes color easily, chocolate does NOT... it's brown. So it's what I use if I need brown.)
- Gel food coloring (can be bought at cake decorating stores, it's what you'll use for coloring the fondant). Gel food coloring comes in about 50 different colors (liquid for airbrushing comes in several hundred, but I'm going to assume you don't have an airbrush)
- Latex or Nitrile gloves (when you're coloring your fondant, you REALLY don't want to also be coloring your hands... that color will stay for a couple days)
- Modeling chocolate (I use white chocolate, so that I can color it rather than paint it. For modeling chocolate you only need chocolate and corn syrup. The less corn syrup you use the more solid the chocolate "clay", more and it becomes something similar to fondant)... if you're using actual toys, you can skip the modeling chocolate. The seaweed on that bottom layer looks like modeling chocolate, but you could use green fondant instead as long as you don't mind it being "flat" instead of 3d like it is in the picture. Or, of course, you could use "toy" seaweed, and toy creatures.
- Pastry Bags OR (what I use, so I don't have to wash the durn things) Gallon Freezer Ziplock bags with the corner cut for the decorating tip.
- Decorating tips - I would need 2 for that cake. One round hole for making the beads, and one with several round holes (for the grass... actually that part is easy, just tedious... you squeeze the bag of green icing.. the holes in the tip make the grass... hopefully at least 10 "blades" at a time, stop squeezing and lift up, do another one right next to it, and another, and another, and another... for the next couple of hours. I suggest drinking wine while doing these types of decorations)
- Pixie Dust (edible, found in cake stores along with fondant, chocolate "chips" -about the size of quarters-, food coloring gel, cake pans, etc. They add a "glow" to the colors. You can match tone to tone, like green metalic dust for the grass... or contrasting to highlight... like a little bit of gold. I'd do blue or silver for the ocean part, etc.)
Phew... okay, so that's the supply list... here's how I would put it all together:
Day 1:
- Bake the cakes
- While the cakes are baking start dying the fondant, and seal in ziplock bags until needed or wrap in cling wrap. Store in frigde
- Make the icing ( http://www.foodnetwork.com/recipes/gale-gand/quick-vanill... )... this recipe would need to probably be quadrupled for the cake you're talking about. But it's easy to make more as you need it.
- Dye one batch of icing green.
- Cool the cakes
- Cut off the "domes" of the cakes.
- Start assembling the cakes....
* Starting with the bottom layer: cut the round or square in half and ice in between. Put the 2 halves back together. Ice the top. Continue doing with each layer so that you have 2 *separate* cakes.
* Ice the entire outside of each cake. (thickly)
* Wrap in plastic and stick in fridge over night.
- Mix the fondant into the right colors. Do this by kneeding the gel coloring in with your (gloved) hands. It'll come out kind of tye dyed looking in the beginning. Keep kneeding until the color is the same throughout.
- Wrap fondant in plastic (or ziplocks) and put in fridge
Day 2
- "Smooth" the layer of icing on the outside of the cakes (I wack it gently with my hands, and then very gently, use a rolling pin -so there is hardly any weight on it)... this creates a smooth base to put the fondant on. With a bumpy base, you end up with bumpy fondant.
- Put cakes back in the fridge
- Start rolling out your colored fondant on a cutting board... you want it to be about 1/4 to 1/2 inch thick and about twice as big as you think you'll need. The thickness keeps it from ripping, and the size means that when you drape it, you don't have "folds", and it just conforms to the size and shape of your cake. Use cornstarch to keep it from sticking as you roll it out. Don't worry, the white color will go away later when you take a damp paper towel to the surface once the cake is assembled.
- Take the first cake out of the fridge and mist with water (helps the fondant stick.to the frosting.
- Slide the first layer of fondant over the cake. Allow it to mold to the form of the cake, and then use a pizza wheel to cut off the excess "skirt". (ball up the left over fondant and put in a bag for later.
- Repeat with base layer of fondant for the 2nd cake.
- Figure out exactly where the 2nd cake will be resting on the first cake
- Stab your bubble tea straws into the bottom layer... so that they support the corners of the top layer, and one in the center. Cut the corner straws flush with cake and leave the center straw long. (Make sure, measuring, that the long straw will NOT go through your fondant for the top layer, cut if necessary)
- Position the hole on the cardboard so that the long straw goes through the center to skewer the top cake, while the others support the board and cake above it, and set the 2nd cake on top of the first.
((Whew! Cake on cake! That part's done!))
- At this point roll out your 2ndary fondant (the darker blue for the waves, etc), and use a pizza wheel to cut the shapes you want. Wipe one side with water and ditto the fondant of the cake you're "sticking" it to.
Once you have the fondant all taken care of, put the cakes back in the fridge and (if you're using it) start working on your modeling chocolate for pawprints, characters, etc. Do as much of the "extra" decorating (piping, starting on the grass, etc. that you happen to feel like, or just leave the cakes covered in the fridge overnight.
DAY 3
All the detail work. Grass, pool, piping, pixie dust, placing the toys or modeling chocolate, etc.
DAY 4 : Party.