It's ok to do all the prep ahead but I would go one step further and cook the dish until it's just cooked.  Then all you have to do is reheat/finish cooking it in a medium oven. Good luck 

Brilliant, thanks for the help..... Fingers crossed!

aka  Scalloped Potatoes ..

Jp205 wrote:

Hi everyone, is it ok to do all the prep and layer all the Potatos and onions and put over the cream a few hours before cooking?

Seems an obvious one but it's my first attempt and have special guests for dinner?

Thanks all!

James

If you notice the description , JP205 is talking about potatoes  dauphinoise .

layered thinly sliced potatoes in a casserole with a sauce usually baked au gratin.   
Now  dauphine potatoes are  a different beast but  for the sake of the intent of the original poster , what they are talking about is pretty much what most in north america would call either scalloped potatoes or potatoes au gratin.

Last edited by Ashen (Sat 14 Apr 12 10:33am)

No she is talking about dauphine potatoes.    They are  like a mashed potato doughnut.   Mashed potato mixed with pastry and fried  into a potato puff.