Is not telling the whole truth the same as a lie?

If it is.. I have no regrets.. well maybe just a little. I've been making Dr. Pepper chicken for a couple years and my husband loves it so much he often requests it, he only knows it as BBQ chicken. His brother came to town so he asked me if I would make it for them this past Saturday. I love my husband dearly.. we've been married for 32 years so I know him well. Let me give you a little insight of my husband. I believe with all my heart that someone read The Princess and the Pea to him one too many times as a child.. he is one of those guys that can smell an odd smell the second he walks in a room.. can detect anything out of place and will whine if he is the least bit uncomfortable. He hates Dr. Pepper, swears it makes him feel ill just to smell it.. for me Dr. Pepper is manna. Yes.. we are complete opposites in every way. Ok.. back to my story.. I made this wonderful meal for them Saturday night, all homemade.. Dr. Pepper chicken, baked beans, potato salad and oatmeal chocolate chip cookies. My brother in law was licking his fingers and going on and on about how good it was and needed the recipe to take home to make for his wife. Now.. my husband is sitting right beside him so I couldn't tell him he has been eating something with Dr. Pepper in it all this time because from this point on every time I make it he will swear he tastes the Dr. Pepper and will drive me crazy until I don't make it anymore so I gave him a simple barbecue chicken recipe that I use to use and is somewhat similar just not as good. Is that wrong? I thought about calling my sister in law and telling her the real recipe but we don't have a close relationship.. it's not bad we just don't communicate at all. Why? I don't know, I talk and text with my brother in law all the time and think of him as my own brother but she and I don't talk at all. I could dwell and try to figure it out but I'm not.. I'm good with it.. lol. Anyway, I started to feel bad after my brother in law left because I know he will think he is doing something wrong when it doesn't taste the same but he tells my husband everything.. and I mean everything... which is what you would expect from a brother but in this case he is NOT MY brother and would take great joy in telling my husband about the secret ingredient... so he cannot be trusted with the truth. Should I tell him so he can enjoy it or leave it alone so we can continue to enjoy it? That is the question..... 

In case you want to try it.. this is the recipe I use
http://www.thirtyhandmadedays.com/2012/04/chicken_recipe/

and this is the oatmeal chocolate chip cookie recipe. I didn't add the cinnamon. They are awesome!
http://livforcake.com/2015/07/oatmeal-chocolate-chip-cookies.html