There are the slight grins we force ourselves to crack, the more genuine happy-to-see you smiles … and then there’s the Good Golly Miss Molly Beam. The latter belongs to Molly Yeh, a rising Food Network star who has such an upbeat personality it’s impossible to remain grumpy around her. Like anyone who makes it onto the Discovery-owned network, Yeh (appropriately pronounced “yay”) knows her way around a kitchen. What differentiates her, though, is how she does that. Sure, every person is an individual, but Yeh truly is in a class by herself as a Chinese Jewish percussionist who moved from Brooklyn to live on a farm in the upper Midwest.