She’s been wearing Birkenstocks – in and out of the kitchen – for years, but chef Gráinne O’Keefe is mildly put out that the footwear has now become a fashion statement. “I live in Birkenstocks because they are really good for your feet and for your back. Now they’re cool, but I had to go through years of getting teased about wearing them. My boyfriend’s always slagging me for wearing old-man shoes.” Her boyfriend is Patrick Chapeau, son of the family who own the building in Ballsbridge where in the summer of 2021 she opened her restaurant, Mae, above the…