Hi everyone! I received my very first large order! My client has ordered a 22x30 vanilla cake. I've never baked anything this ginormous so I need a little help and I appreciate everything I can get. Here's the research I've gathered so far.

Use four 12x18 sheet pans to trim and make a two layer 22x30.

Must have a STRONG cardboard base.

Needs to be frozen for 30 min prior to crumb coating, trimming, and stacking.

So my client wants sliced strawberries and bananas for a filling in the cake. I was thinking about using a stabilized whipped cream for the filling and decorating/frosting/decorating using a Swiss buttercream. I'm worried the weight of the cake will make the whipped cream ooze. 

Should I just use Swiss buttercream for the entire cake and even the filling? What kind of filling or frosting would work best for a cake this size? 

I would suggest to make regular buttercream and for filling use commercial bavarian cream that comes in those 2lb plastic sleeves.  Then mix in the strawberries and bananas.  You should freeze your sheet cakes ahead of time so they're easier to handle.  I don't quite understand your dimentions.  Do you want a 4 inch high cake?  Or are you making them a single layer and then splitting them for a filling between?

if you do it like you said, sweet4yu, then you have to keep it refrigerated with the whipped cream --

if you do it like cakemaker says then you need to do it last minute or keep it fridged -- and it probably will not fit in your home fridge you will need a walk in -- i'm not even sure it would fit in my commercial fridge with a cake 30" the board will need to be bigger than that --

sometimes i make a board to just fit the cake size then place it on the display board when i deliver to help juggle sizes in and out the fridge and boxes and cars --

i would recommend using half inch foam core board for this or masonite board -- got to lowe's and get them to cut you something -- not plywood it's too heavy -- and that's another thing -- you'll probably need a helper to deliver it and you need to calculate your doorways/elevators/stairways things like this -- it'll fit in a van

I was a little confusd by the math at first but I realized you're cutting it down right?  It would be less wasteful to use 11" x 15"s.  I agree with K8, don't use cardboard you'll end up with a ton of cracks everytime you try to move it.  I did two separate 11" x 15" x 4" recently and the foam core is great.  It's lightweight and vey sturdy.  You'll need to get it thick for all that weight, mine was 1/2", you'll need thicker than that.  I used swiss buttercream for mine as well.  I would make a fruit flavored or chocolate swiss bc over something that needs refrigeration.  Good luck!

If piecing together to get the size you need,  if possible, offset the seams so they don't all line up vertically.  Lay out your bottom layer pieces and fill, then trim and lay on the upper layer pieces of cake, but overlap or lay it out the reverse of the lower one so the seams don't line up.  That will also make it less likely to crack at the seams.  Hope that make sense.  And definitely a non flexible base.  foamcore, or masonite as mentioned above, or I have 1/2" white food grade plastic (like they use on cutting boards)  custom cut at my local Tap plastic into various shapes and sizes, and I love them.  Not too heavy, extremely strong, totally food safe, and completely reusable, but only if you can get the board back!  HTH

oh yortma -- great idea those nice plastic cutting boards -- we have a real nice restaurant supply place that went retail and they have the best prices for one and for another they have those lovely white cutting boards in a variety of really generous sizes -- oh perfect idea -- good one!

Thank you guys for all the amazing responses!  So heres my game plan...

I just bought two 11x15x2 cake pans and I'll be using them both to make the 22x30 cake.

I'm going to head to Lowes/Staples to get a foam core board to use as the base for my cake.  I'll also get a larger, prettier cake board to put underneath that.

The cake will be TMNT theme with colored macarons and fondant accents.  Here's my schedule.

Thursday: Buy boards, box, and rolled fondant.  Make fondant accents and refridgerate.

Friday (I have all day): Bake, freeze, fill, and dirty ice the TWO 11x15 cakes separately and put into fridge overnight.  Make macarons.

Saturday: Take cake out of fridge, Put the cakes together, decorate and deliver by 6pm.

So what do you guys think?  Good plan?  Terrible plan?  Am I out of my mind? Hahahaha