Take a look at the item again:
Hands covered in cookie dough, (A)
Madeline ran to the phone, (B)
hoping that the call was from Eric.
(C) Her boyfriend who
had broken his promise to call the day before.
You wanted to do this:
Hands covered in cookie dough Madeline ran
to the phone, hoping that the call was from Eric. Her boyfriend who had
broken his promise to call the day before.
Removing the comma after dough is an error. Covered in cookie dough is a past participle phrase. When such a phrase introduces a main clause, you need a comma to connect the two parts.
You might want to review the rules.
Go back to the sentence to try again.