I've had a busy few months meeting some awesome clients, and creating some REALLY fun cakes for their events. The foot-long sub sandwich cake was a HOOT to make. Here are some detailed instructions of how to make a sub sandwich cake.
Cake, and sub bun assembly:
I baked a 14" square cake and cut it into four 3 1/4 x 12" sections. I cut 2 pieces of cardboard to 3 1/8 x 11 7/8" which will be the base for the buns. I placed one cake section on a cardboard base, and slathered buttercream icing on it; I topped it with a second section of cake. This will be one of the buns (top or bottom - doesn't matter which). I repeated this with the 3rd and 4th cut pieces of cake, placing them on the 2nd piece of cardboard. You will now have 2 2-layer pieces of cake 3 1/4" x 12". Carefully carve the edges of the buns for a smooth, rounded edge. I crumb-coated the two buns with a very thin layer of buttercream icing and chilled them well.
Coloring the fondant:
1) For the bun, I mixed a little brown food coloring into some white fondant for the 'wheat' bread.
2) Mix two shades of green for the lettuce.
3) Deep red for the tomato.
4) Light pink for ham.
5) Off-white/beige for turkey.
6) Yellow-orange for cheddar cheese.
I actually placed real ham, cheese, lettuce, etc. on the counter while I mixed the colored fondant. Afterall, I want this sandwich to look as real as possible! This is the most time-consuming part of the process but great to prep while the cake is cooling.
Covering the buns in fondant:
Roll out a section of the light brown fondant for one of the buns. Pull one of the chilled sub buns from refrigerator and lay the rolled fondant over the bun, gently easing the sides down over the edges of the cake to the base cardboard. Cut away any excess fondant with a pizza cutter. Make slight impressions in the 'top' bun as if the bun was scored and the bread has risen (see photo of top bun). Place this bun in the refrigerator while you lay another section of fondant over the bottom bun. No impressions are necessary on the bottom bun. Chill both buns well (at least an hour).
Making lettuce, tomato. ham, turkey, and cheddar cheese filling:
For lettuce, take each shade of green and twist together. Roll out to 1/8" thickness. You will see a marbling affect from the 2 shades of green coloring. Cut into strips ~ 1/4 - 3/8" wide by 3" long. Add a thin layer of buttercream over the CENTER of the bottom bun - try not to get the icing on the edges of the bun. Lay the strips of lettuce on the buttercream, pressing gently to secure and covering the bottom bun.
Roll out the red fondant to ~ 3/8" thickness. Cut tomato slices with 2 - 3" round cutter. Using a modeling tool, 'etch' impressions into the fondant like that of a slice of tomato. Place each slice of tomato on top of the lettuce securing with buttercream.
For the ham and turkey, roll out the colored fondant to 1/4" thickness and cut with a 5" round cutter. Roll each cut piece to ~ 1/8" thickness. Don't worry if the piece is no longer round - deli meat is not round either. Carefully lay the cut piece with a fold and place on the bottom bun. Add a little buttercream icing to make it stick. Do the same for ham and turkey. Brush the edges of the ham and turkey with brown food coloring (mix with a small amount of almond flavoring).
For the cheddar cheese slices, roll out the yellow-orange fondant to 1/8" thickness. Cut into 3 1/2" squares; cut the squares in half to form triangles. Lay the triangles of cheese over the 'meat.'
Adding dowels or straws to support top bun:
I like to use straws (bubble straws or regular) to support my cakes. Place 3 - 4 straws through the cheese/meat/lettuce and push each through the bottom bun. These supports should be distributed about every 3". Mark each straw so you know where to cut it; pull the straw out, cut, and place it back into the base sub bun. Each straw should be cut at the same length.
Place a small amount of buttercream over the CENTER of the cheese/meat and add the top bun which will rest on the straws. Press down slightly to adhere the bun and buttercream. Chill well.
Finishing touches:
To add 'baking' marks on the bread, mix a small amount of brown food coloring with almond extract or vodka. Using a 2" pastry brush, lightly dab or brush the buns to add a lovely brown baked color. Add deeper brown coloring to the top bun brushing on the impressions made earlier.
Add skewers if you'd like to secure the whole cake together. I used 2 bamboo skewers which I pressed through the top bun, cheese/meat/lettuce, and through the bottom bun.
Finally, I placed the sub sandwich on a cardboard base covered with a real SUBWAY sandwich paper, and added a 2nd piece of SUBWAY paper directly under the sandwich crinkling it slightly to look like it was just unwrapped.
Enjoy!
