"Are you going swimming?” Joshua McFadden asks without lifting his head from the candy-stripe beets he’s slicing paper-thin. He’s talking to Sara Kramer, his co-chef for the weekend, who is bent over the counter measuring buckwheat flour for the night’s dessert. She declines his offer; she’s got flatbreads to roll and yogurt sauce to mix. There are hours to go before lunch, and though it’s nearly noon, no one’s too concerned. At this lake house in Maine, time doesn’t work the way it does elsewhere....