This year my eldest son wanted a hamburger cake for his 12th birthday. Apparently we don't eat nearly enough hamburgers for his liking. I don't know why, but other than salmon burgers I am not a big fan of your average burger. But Max, he loves them with a passion.
Here's what I did first: baked two 9" round vanilla cakes. Then I baked a double chocolate rectangle (I only needed half this as it turned out), out of which I cut another, slightly larger, circle. I wanted the "burger" part to hang out slightly. For this part of the cake I'd advise a solid, dense cake, with very little crumb, because you won't want it shedding while you're icing it.
Then, as you can see from the photo, I cut one vanilla cake horizontally for the "bun" bottom, and one vanilla cake horizontally for the "bun" top. You could use one cake, I suppose, but I wanted the "bun" to be slightly larger than a half of a cake, so for the "bun" bottom I just shaved off the top; ditto for the top portion of the "bun."
Next, cut out a circle of chocolate cake for the hamburger patty. I simply laid the 9" tin on the cake, and cut away a slightly larger circle.
Then I stuck them together with some ganache, made the night before so it would be thick and cool. Need a ganache recipe? Here's mine:
Chop up 13 ounces of chocolate (or use chips), place them in your food processor, then, with the motor running, slowly pour in 1 & 1/4 cups hot whipping cream. Process until smooth. Pour into a bowl and leave it for a few hours to cool.
Then I used a buttercream icing to frost the details. Need an easy buttercream recipe? Here's mine:
1/2 c Crisco (make sure it's all vegetable)
1/2 c butter
1.5 c icing sugar
milk to thin (no more than 1/4 c)
Put everything in your mixmaster or Kitchen-Aid and blend on high for 5 minutes. Makes a lovely silky buttercream.
Initially I used Wilton's Brown gel for the "patty," but either I had an old gel or I was feeling particularly colour-blind, but that brown wasn't what I'd call brown, so I scraped it off and wondered what to do instead. I might even have panicked a little, because the Party was at that point only an hour or so away. Then I decided to thin the left-over ganache with a couple of blobs of butter, in the food processor, and add some icing sugar and milk, to make a sort of icing. This I patted on with a knife, trying to make it knobbly like ground meat.
I also found myself slightly distressed by the tan/skin colour that I'd intended to use for the bun portion, because that had a distinct reddish tinge to it. I added some yellow and brown, and eventually got something more to my liking. I need to find some better colouring gels though, because the red was similarly at odds with my idea of red. I ended up using red gel in those decorator tubes you can get in the grocery stores. Fortunately the green and I got along fine. I used decorator tip #67 for the "lettuce." I was going to use pine nuts or sesame seeds for the seeds on the top of the bun, but I ended up using yellow decorator's sugar because I had no pine nuts and I wondered about having sesame seeds on a cake. Seemed slightly incongruous.
The kids all gasped and said "A hamburger cake? Wow!" when we brought it out, which was really all I wanted to hear. I'd instructed a friend of mine to say "Wow! Is that a hamburger?" just in case it was unrecognizable and no one knew what the heck it was, and she said it, much to our mutual hilarity, but fortunately it wasn't necessary. Max was quite delighted.