Welcome to the Cake Decorators Q&A

Good evening, I have my first commission, a 14 inch square chocolate cake.. Please advise on quantities and suggestion of recipes that will be appropriate. It’s a wedding reception cake. It’s a bit scary lol

http://www.bbcgoodfood.com/recipes/4577/wedding-cake-rich-dark-chocolate-cake
a wedding cake base for a chocolate wedding cake that should do the trick. It is by Jane Hornsby and it tastes wonderful.

Hello Maria-Anna

Any recipe can be be scaled up or down by using either my ready reckoner tool or the cakeometer tool here:

What Size cake tin to use

I can appreciate that baking such a large cake is scary so I would just like to ask whether you have baked a cake of this proportions in your oven before. Large cakes can be tricky at best. There are several factors which should be taken into consideration before going ahead with baking one.
You’ll need to establish whether your oven has suffcient room to accommodate a 14″ cake tin comfortably. Will the oven door close without the tin touching the glass and the sides of the oven walls?
There should be plenty of all round space for an even heat distribution otherwise the cake will not bake at all properly. The centre of large cakes take a lot longer to cook than the outside. With square cakes in particular, this will leave the corners vulnerable to burning well before the centre has had a chance to set. Consideration should also be given to the type of recipe being baked. Some recipes are not suitable for scaling up in deep tins beyond a certain size.
To understand a little more about baking problems and solutions please take a peek at my blog here:

Baking Problems and Solutions by madeitwithlove

For best results I would suggest baking several shallow sheet cakes/ flat cakes. These can be filled and stacked then cut off to your 14″ square. This will ensure a properly baked cake in far less time.
Jane Hornby’s chocolate cake recipe is very good. I recommended it to site members about four years ago. Since then it has received great feed back from all who have tried it. However it is still advisable to bake a sample cake before altering to larger proportions or if trying it as a sheet cake.
Other chocolate cakes recipes of interest, including Paul’s delicious moist chocolate cake are discussed in this thread:

‘Paul’s moist chocolate cake’ My feed back

Hope the above links help you make some informed choices.