Oat flour comes across as an exotic ingredient in a recipe until you realize that all it is, is well oats. Ground. And that it is so simple to make it will have you craving oaty goodness! If you poke around the interwebs you will see many sites on how to grind the oats. After trying out a couple of methods I can say this:
Don’t waste your time with a blender, unless you have a high-speed blender, such as a Vitamix. My feeling is it is recommended to use as most houses have one, where as a food processor or well powered mini-food chopper isn’t as common. The blender was frustrating, slow to grind and leaving uneven chunks. Instead I pulled out my mini chopper and processed about 1 cup oats at a time and had gorgeous flour quickly. The sharp blade cut right through.
With large batches a food processor works quickly. But the beauty of oat flour is you can make just what you need, right before you need it. And it keeps it fresher when it stays as oats until it is needed.
A cup of old-fashioned oats will produce about 6 to 7 Tablespoons worth of flour (or about 7/8ths of a cup).
Producing a rustic flour:
For a even finer flour, use a Vitamix dry grains container:
This will produce a very fine texture. Start slow, and work up. You will need to turn off and shake the container once or twice, to keep it grinding.