Cake is perishable, so if you have your cake, rejoice. Eat your cake, leaves nothing.
If, it isn’t gone already? Should someone else find it!
While the fantasy sounds good, it is fleeting.
But if you come close, remember; “Don’t bite the hand that feeds you!”.
When a person mistakenly wishes and uses this to get both or all of what they want. When used negatively to express the impossibility is better usage.