"Laverne & Shirley" was a spin-off of which TV show?

"Laverne & Shirley" spun off from "Happy Days" after the characters appeared as dates for Richie and Fonzie in a 1975 episode. The show proved so popular it actually outperformed its parent series in the ratings, landing at #1 for multiple seasons while Penny Marshall and Cindy Williams turned their characters into household names with their physical comedy and undeniable chemistry.