I thought I was being well prepared. I made up some batter to be frozen in the pans I'd bake them in. The batter in the pans and the leftover batter in a freezer bag, have been in the freezer for about 2 hours now.

I sat down; got on CC, the recipe was already on the screen and when I looked I realized the recipe called for 1 Tblsp. of butter flavor and I only put in 1 tsp. I don't want to skip the other 2 tsps. Please don't tell me I have to re buy ingredients to remake this batter? Is there a way I can add more butter flavor to the two pans, would I have to put the batter back in the mixer and add more or can I add some while it's still in the pan?

I wouldn't worry about it. It's only flavor, at least..just make sure your filling has good flavor. Now, if it was leavening or eggs, sugar ect...you might have problems.
You might not even notice.
Blessings~

I agree--I wouldn't toss it out for that. A Tablespoon of butter flavor sounds like an awful lot to me anyway.