Best eaten on the day they are made, otherwise store in an airtight container for 1 to 2 days. Reheat in an oven preheated to 150 degrees C (300 degrees F)/gas mark 2 for about 8 minutes. Best served warm. To freeze, stack fully cooled muffins in an airtight container with baking parchment between the layers, or wrap individually in plastic wrap, then put in a resealable bag. Freeze for up to 3 months. Defrost on a wire rack for about 1 hour. Reheat as above.