01 - 
                Preheat to 375°F and cover a baking sheet with parchment paper.
              
              
              
                02 - 
                Lay the crescent dough flat and press all the seams together to form a smooth sheet.
              
              
              
                03 - 
                If you like, spread mustard across the dough. Lay out the ham slices evenly, then layer cheese on top.
              
              
              
                04 - 
                Roll the dough tightly into a log, starting along the longer edge. Slice it into 1-inch pieces.
              
              
              
                05 - 
                Arrange the cut pieces on the parchment-lined tray. Brush with the melted butter and sprinkle poppy seeds on top, if you'd like.
              
              
              
                06 - 
                Bake for 12-15 minutes, or until they're golden and the cheese is bubbly.