[s9e8] — The Lighthouse
Robin attempts to bond with Barney's mother, Loretta, leading to a "scrambled egg-off" to decide who makes better eggs. Loretta eventually concedes when she realizes Robin's efforts come from a place of genuine care for Barney.
Barney's talk about scrambled eggs inspiring classic rock songs is a nod to "Yesterday," which Paul McCartney famously titled "Scrambled Eggs" as a working title. [S9E8] The Lighthouse
Two years after meeting (May 2015), Ted takes the Mother to the lighthouse. Despite her initial reluctance to climb the stairs due to being tired, they reach the top where Ted proposes, and she enthusiastically says yes. Robin attempts to bond with Barney's mother, Loretta,

