I don't recommend using a food processor simply because rolled oats can easily pulse into the flour with a large blade. The small blade of the blender makes it easier to create a smooth muffin batter. If you only have a food processor, you have two options: - Replace rolled oats with wheat flour. Don't add the wheat flour to the blender. Add it to a separate large mixing bowl. Then, blend the remaining ingredients, pour the liquid batter onto the flour and combine until smooth. - Pulse rolled oats into flour first. Then, when the flour is fine, add the remaining ingredients and blend until smooth.