Game Help Talk:Sims 3 Skills/Cooking
From SimsWiki
The Ambrosia dish can only be made with Perfect Life Fruit and Perfect Deathfish. So it is important to reach level 10 in the Gardening and Fishing. Then work hard raising Life Fruit until the Perfect level is reached. The same with fishing for the Deathfish you have to do alot of work to catch the Perfect Deathfish.