Ok I thought I was in unethical life pro tips subreddit. I'm not, but I'll still give my unethical tip: Tell Brenda privately that your [insert person here] was in town and made the cake she likes so much. Tell Brenda you're a big fat phoney and you can't really bake. Be sure to tell her that you mentioned that your [person] made them the day you brought the cake in but it somehow got lost in translation and you were too timid to correct every one. Then say you were too timid to tell Brenda the truth because you figured she was just giving you a super high compliment about the birthday cake thing. Now when Brenda tells the whole office you didn't actually make the cake you just gaslight every one and say "Yeah I said that the day of but every one left and talked about it as if baked it, which I didn't."