I have a bride that wants a three tiered cake PLUS a sheet cake to serve from the kitchen. Wondering if the sheet cake should be 1. One layer of cake (12x18 x2) torted and filled...
or 2. Should it be (12x18x4) which would be 2 layers of cake with filling in between?

If the answer is #1, is the charge half of what you normally charge?

Hope I that makes sense.

Up to you...

For me, a 1/2 sheet (which is what they really want) cake generally is 2 layers, 1 filling, 2" tall. A wedding cake is 4 layers, 3 fillings, 4" tall. So I only offer "kitchen cakes", which are 12x18, 4 layers, 3 fillings, 4" tall to match the original wedding cake in size. Kitchen cakes generally cost the same amount as the main cake's base price.

I have seen others that will do the 2" tall 1/2 sheet for "in the back", but the guests are getting served 1/2 a piece of cake since they are only getting 2 layers instead of 4.

Everyone has different names for things... but basically your option #1 is a "sheet cake" or "slab cake" and your option #2 is a "kitchen cake". I offer kitchen cakes at $3.50 per serving (no borders, no decor, not even a sexy board. also they are always rounds as those are easier for me to assemble and ice) as compared to a base tiered cake price of $7.75. I also require a minimum of 100 servings in the centerpiece cake before we incorporate them.

Anyway, it "should be" what the customer wants/expects it to be. Ask them and price accordingly.