Leftover burgers will keep in an airtight container in the fridge for 2-3 days, or you can freeze them up to 1 month. Freeze burgers flat then wrap in plastic wrap and then tin foil. Store in a ziplock freezer bag.
* To coarsely chop the oats, add 1/2 cup rolled oats into a food processor. Process the oats until a coarse meal forms (the chopped pieces will be a mixture of powder and chopped oats just smaller than rice). Be sure not to process too long or the oats will turn into flour.