Why are you trying to “fix” her? Why are you trying to train her to make chocolate chip cookies? Did she ask you to teach her how to make chocolate chip cookie? Surely, she can tell that what she produced wasn’t the same as the chocolate chip cookies you made. Maybe she likes them this way. Maybe she likes the autonomy of making cookies however she damn well wants.
Quite honestly, i would leave a man who was trying to train me, unless it was a skill i specifically asked for help with.
She offered you a chocolate chip muffin. Say thanks, and either eat it and enjoy the muffin, or don’t eat it if you don’t care for chocolate chip muffins. Don’t harass her about how many eggs she used.
Jmo