All-Purpose Flour (Best Option)
1:1 by volumeAll-purpose flour contains a moderate protein content (around 10-12%) which is close to bread flour's higher protein content (12-14%). This allows it to provide enough structure and thickening properties when mixed into oatmeal, preserving the desired mouthfeel.
When using all-purpose flour, ensure to whisk it well into the oatmeal to avoid lumps. The cooking time and liquid ratio can remain unchanged, but expect a slightly softer texture.
Compared to bread flour, the oatmeal will be marginally less chewy and robust but still thick and satisfying, making it the most practical and accessible substitute.