Cool leftover pancakes in a single layer for 20 minutes, then refrigerate them in a shallow airtight container for up to 4 days. Place parchment between layers so the rough edges don't stick. For freezing, arrange the cold pancakes separately until firm for 1 hour. Then wrap pairs tightly and store them in a freezer bag for up to 2 months. Reheat refrigerated pancakes at 400°F for 8 to 10 minutes, or toast them in a 350°F skillet for 2 minutes per side. Frozen pancakes need 12 to 14 minutes at 400°F and don't require thawing. Add fresh chives after reheating, not before. Discard pancakes with a sour smell, gray moisture, slimy surfaces or visible mold.