Answer: The answer is 'Bridget liked to grill hamburgers, and her friend liked to bake cookies'.
Explanation: A compound sentence are 2 independent clauses connected by a coordinating conjunction. 'Bridget liked to grill hamburgers' can stand alone as a sentence, making it a independent clause. 'Her friend liked to bake cookies' is also a independent clause because it can be a sentence by itself. 'And' is the coordinating conjunction, as it links the clauses together.