Mitt Romney's 66th birthday involves Diet Coke, fluffernutter cupcakes and a party hat

Mitt Romney may have lost the White House, but at least he has cupcakes.

"Happy 66th Dad. Can't beat a fluffernutter cupcake," Tagg Romney captioned an Instagram photo of his father's low-key birthday celebration at the office Tuesday. In one photo, Romney poses in a pointy party hat with a boxed lunch, a Diet Coke and several fluffernutter cupcakes lit with candles. In another, he has cupcake icing smeared on his lips.

Romney has been criticized for his failure to relate personally to voters, but in the months since an election lost that reportedly left him "shellshocked," the former governor has been spotted at Costco, pumping his own gas and riding rollercoasters at Disneyland.

[Instagram]