hi, I am trying to make a space shuttle cake for ds space birthday and have found a simple-ish way to do the icing and shape I think I can manage online but I will need to make it bigger.... ds loves chocolate cake so was hoping to use the recipe on mnet
A 7" Rd Pan will fit into your roasting dish 3.7 times. It then depends on how thick you want your cake. Bear in miind that the original recipe to which you refer is for two layers of cake.
As for the timings, although the cake will cook from the top and bottom (through the pan), the middle of the cake is slightly further away from the sides of the pan than if you were using a 7" Sandwich Pan. You may need to leave it in the oven for a little longer.
3rdnparty, if you round up 3.7 to 4 it is probably easier to do the maths. 4 x the recipe will fill your roasting dish to the height of your 2 layered sandwich. 2 x the recipe will fill your dish to the height of one layer of your sandwich.
As for lining, foil, being aluminium, will not reduce the heat. Furthermore, putting any lining around the side will inhibit the heat just where you actually need the heat. The think to do would be to pop a sheet of greaseproof paper loosely over the top to stop it drying out.