The cafe tables were empty at Loretta’s Authentic Pralines down in Faubourg Marigny and the display cases up front were barren. But in back, Loretta Harrison and her crew had the kitchen humming. Another batch of pralines bubbled in a copper kettle. The homey aroma of sweet potato pies in the oven filled the air. Harrison wore a pink facemask and a dusting of flour on her apron as she rolled more dough for the next round of pecan pies.