Take a look at the original sentence again:
As Irene scooped stuffing out of the Thanksgiving turkey, she saw gold glinting
from the breadcrumbs, finally, she had found
her earring, which she had lost early that morning.
You chose to fix it the correct way:
As Irene scooped stuffing out of the Thanksgiving turkey, she saw gold glinting
from the breadcrumbs; finally, she had found
her earring, which she had lost early that morning.
She saw gold glinting from the breadcrumbs is a main clause. Finally, she had found her earring is the second main clause. You are always correct when you use a semicolon between the two main clauses that create the comma splice.