Valerie Graves, 55, was found dead in bed at about 10am on December 30 2013 on the ground floor of a seaside house in Bosham.
Cristian Sabou, 27, appeared at Brighton Magistrates' Court on Saturday after he was held on a European Arrest Warrant last week at his home in Dej, in the north-west of his native Romania.
He was flanked by two security officers as he stood in the dock, wearing a patterned white t-shirt and with short hair and stubble, and showed no reaction as the charge was read out.
With the help of a Romanian interpreter, he spoke only to confirm his name, date of birth and nationality.
No plea was entered during the five-minute hearing and the presiding justice, Barney Miller, remanded Sabou in custody ahead of a hearing at Lewes Crown Court on July 23.
Sussex Police said Sabou was extradited to the UK on Friday.
He allegedly murdered Ms Graves - who had moved from Scotland to Bracklesham Bay, West Sussex, shortly before her death - between December 28 and 31, according to the charge read out in court.
Ms Graves died just days after her birthday, which was on Christmas Day, while house-sitting at the mansion in Smuggler's Lane with her mother Eileen, sister Jan and sister's partner Nigel Acres.
A post-mortem examination found she had severe head injuries after being hit with a claw hammer, probably at about midnight.