1/4 cup unsalted butter 3 large yellow onions, peeled and sliced 1/2 teaspoon ground white pepper 1 1/2 teaspoons dried thyme 1/4 cup all-purpose flour 1 1/2 cups dry sherry 1 quart low sodium chicken stock 2 cups heavy cream 1 tablespoon kosher salt 1 tablespoon lemon juice 1 teaspoon hot sauce 2 twists of…