Since you need the shift in verb tense, both verbs have to be in the past. So, the correct answer should be - For the upcoming bake sale at the fair, we baked the cake and FROSTED it.
Correct: For the up coming bake sale at the fair, we will bake the cake and frost it.
Because both parts need to match in future tense. Upcoming bake sale is future tense while 'baked' is past tense
I am sometimes unable to apologise myself in front of others rarely , but I'll apologize to them so that they can't even see me and I can apologize that makes my inner soul happy