Place oats in a food processor (or a blender) and pulse the oats until they are ground into a powder-like consistency. This process should take about 60 to 90 seconds.
Stop and stir to ensure that all the oats have been finely ground. Pulse until again, if needed.
Notes
Scale up or down the recipe as needed
Store extra flour in a labeled air-tight container for up to 3 months
Recipe is gluten-free only when certified gluten-free oats are used
Use whole or steel-cut oats. Quick-cooking or instant oats should not be used to make oat flour.