How more nicer can you be then how itsmylife worded it? I hope you don't mind me using that little note myself! Very well said itsmylife!!
As far as forgiving goes. IMO forgiving means no more worrying about the person/situation anymore. If your worrying about it then I doubt you've forgiven. If it's bothering you then it's not forgiven. It means move on & be able to talk to that person whenever you see them. You might not be as close friends anymore but that doesn't mean you haven't forgiven. Pray about it first & let things settle down. Everything will be ok.
I'd still email what itsmylife suggested, it won't hurt a thing. 
This lady might just need several reminders.
the cakes came out great!!!
i agree with alot of people on here....send a nice note along with all the conversations you two have had....with an itemized bill....
good luck!!!! i have a feeling this will be resolved....you are such a lovely person to not want to rock the boat...but you do need to get your $ for the ingredients!!!!
I can't believe the nerve of some people. You were kind enough to do this as a gift, then she makes yu chase her down for the money! She should be ashamed of herself.
wow, how unappreciative can you get??? You donated your time to this and then she doesn't have the decency to pay you back for the ingredients?? I guess next time, you should send her a grocery list before baking for people. Don't make a cake unless they've given you the ingredients 
Good luck. I hope she finally pays you back. If not, I'd let her husband know since they're both probably in charge of the money.
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