Add oats to a high-speed blender or food processor. Use roughly 2 cups oats to start.

Blend the oats on high speed for 20-30 seconds, stopping to stir or shake periodically. They should grind down into a fine, flour-like powder.

Keep blending in short 5-second bursts and shaking the blender to get the oats as fine as possible. It should feel smooth like regular flour when done.

For storage, transfer the freshly made oat powder to an airtight container. Enjoy in baked goods or store for later use.