So, in the spirit of letting others learn from my mistakes, I bring you my step by step Guide To Making A Fire Truck Cake. Please note that I have never taken a cake decorating class. I can't pipe a beautiful rosette, or sculpt a scale-model medieval castle from gum paste. I did not walk to the fire station and take pictures first, so this cake is what fire trucks kind of look like in my head, but would cause you to panic if one like it arrived at your house for the purpose of flame extinguishment. I am a good baker, but a lousy decorator. So this is not a Duff Goldman cake. (Which, incidentally, are beautiful but don't taste so good.) This is a Mom Cake. This is a cake that suffered cake slumpage after being beset by cats and had to then be reinforced with bamboo skewers.
First things first. I recommend using a firm cake recipe for any kind of sculpted cake. I like the Magnolia cake recipes because they're slightly dense. If you want to use a mix, do the thing where you add pudding to make a kind of pound cake. Use 2-3 recipes/mixes per fire truck, depending on how tall you want the cake. I did 3 for each of these. The yellow cake is yellow cake (see what I did there?) and the red cake is chocolate.
I use the Magnolia buttercream recipe for almost every buttercreamed baked good I make. It's very tasty and very easy. The yellow cake is filled with vanilla buttercream and the chocolate cake with chocolate buttercream. (Which I make by replacing some of the vanilla's powdered sugar with cocoa powder.) Both are frosted with tinted vanilla. It took about half a batch to fill each cake and one batch to frost. Make all of the frosting at once (or in two batches, whatever you can do in your mixer bowl) and tint separately.
The yellow frosting was colored with a small amount of Wilton's Lemon Yellow gel coloring. The red frosting took three whole containers of No-Taste Red to color, which is typical for red. The color deepens and intensifies over time, so don't worry if it looks a little magenta at first. And definitely get the No-Taste Red because otherwise your cake will taste like evil.
For the silver, take some vanilla frosting and stir in some black decorating icing (the tube kind) from the store until you have a nice metallic gray. They make black gel icing but sometimes the color goes all weird and you'll need black for the wiper blades and stuff, so I say go for the tube.
Or, if you like, skip making your own and buy containers of vanilla frosting and tint.
1 sheet cake pan
Disposable pastry bags (Ziplocs work okay too)
1 large offset spatula
1 small offset spatula
Silicone pastry brush
Bamboo skewers (if you have cats)
Cake board (foil covered cookie sheets are great)
2-3 batches of cake batter per fire truck
Roughly 1.5 batches of buttercream total per fire truck Meringue powder
Gel food colorings
1 tube black icing
Mini chocolate frosted donuts
Okay, these pictures are pretty bad, but I was in a hurry.
Step One: Mix up the batter
I mixed the batters separately in my stand mixer, then combined them in a Tupperware vat to mix them all together. It was a lot of cake. You'll probably have to bake it longer than usual if you use 3 batters. If you go with 2, you'll probably have to underbake so it's not too dry. Just keep checking.
Step Two: Trim the cake
After the cake has cooled and you've turned it out of the pan, use a very sharp knife to even up the top and sides. If you like, freeze the cake and do all of the cutting frozen. I had to do that with a Mad Hatter-style cake I made once. It made things much easier.
Step Three: Cut the pieces
The cake is 17 inches wide and after trimming, I cut it into three sections of about 5 2/3 inches wide. One of these thirds was then cut into thirds along the width, each third being about 3 3/4 inches. Behold:
Step Four: Laying out the pieces
The two big pieces are the body of the cake and the three small ones are the cab. I set it up just to see what needs trimming and so forth. Note that I cut out a chunk from part of the top layer of the truck body. That's for that metal compartment on the fire truck.
Step Four: Glue it together
Spread thickly with buttercream and stack everything together. After gluing, I cut a slant from the top front of the cab for the windshield area.
Step Five: Crumb coat
Please crumb coat your cakes. It's easy and you will be glad you did. A crumb coat is just a very thin layer of frosting put on the cake to make the cake smooth when the time comes to put on the final coat. Use a silicone pastry brush (they're like $4 at the grocery store) to brush all the loose crumbs off. Then spread a very thin layer of frosting over the whole cake. Let the crumb coat sit for at least an hour. I covered mine with plastic wrap and left them over night, or you can take this time to make your royal icing.
Step Six: Ladders and glass
I used royal icing to pipe the ladders, windows, and windshields. Do not be scared of this. It is very easy, even for the severely Coordination Impaired such as myself. Royal icing is simply meringue powder, water, and powdered sugar. You beat it in your mixer, glop it into a pastry bag, snip a weensy little hole in the end, and have fun. I love it for cookies because you can flood with it.
I drew a template on white paper, taped it to a cutting board, taped waxed paper over my template, and made all the pieces for my ladder. The ladder pieces need about 6 hours to dry and the windows would do best overnight. You'll know when they're ready because they'll come right off the wax paper. Just be careful because they are fragile. After they were dry , I used more royal icing to glue the ladder together. Let the completed ladder dry over night at least.
If you've never used a piping bag before, you can watch this video here. I don't bother using a coupler and tip for stuff like this. Just use scissors to snip a tiny (really tiny - like 1/8 of an inch) piece off the end.
Note: The picture of the completed ladder was taken with my new camera. Even though I don't know how to really use it yet, the difference in image quality is impressive I think.
Step Seven: Frosting and decorating the cake
Spread a generous layer of tinted buttercream over your crumb coat. If it's sticking, it's probably too thick. Whip a little milk into the frosting until it spreads smoothly. Also, keep a glass of water handy to dip your spatula in and smooth over rough spots as needed. Not too often or you'll sog the cake, but a little is okay.
Spread the silver frosting over the indentation you made between the body and the cab. Pipe a silver border around the base and over the wheels if you like, and use the small offset spatula to make the bumper. Use the mini donuts as wheels and put a dot of silver in the center of each for a hubcap.
Use whatever candies strike your fancy for the rest of it. I used Tootsie Pop Drops, a Rolo, and a licorice allsort for the top. The doodads on the side are mini jujubees, the headlights are licorice allsorts. The red cake has some licorice wheels on the silver part to help disguise the slumpage-induced crack. I got all of the candies from the bulk candy bins at Wegman's. The hose thingies on the side are Oreo cookie straws. I stuck toothpicks into them, spiked those into the cake and, for good measure, used a ledge made of a popsicle stick. In retrospect I would have skipped the ledge because I don't like non-edible decorations on cakes.
Perch the ladder on top, and voila! (Note the enucleated red cake in the background. SIGH.)
At first I considered doing this in fondant, but even marshmallow fondant doesn't taste great. I also thought about doing a lot more detail, like a bi-color top and also making a little door with a shield and a latch on it, but I think this is fine for a 4 year old's party, to be honest with you. He seemed happy, anyway!