If using butter plus baking paper on a baking sheet doesn't work, consider using a no-stick spray. However, you'll want to make sure that the no-stick spray doesn't use any synthetic ingredients or additives that could change the flavor or nutritional content of your flapjacks. Butter should work for most folks. When in doubt, add a little more butter to the bottom of the baking sheet to reduce the likelihood of the flapjacks sticking to near zero.