Cake flour is “softer” than all-purpose flour. What this means is that it has a lower protein content and will produce a more tender crumb. You would want to use cake flour in many cake recipes, but not in a bread recipe, for instance. Bread flour has an even higher protein content than all-purpose.   In the gluten-free world we have various flours and blends at our disposal that are also low FODMAP. As many of you know, I believe that Bob’s Red Mill 1 to 1 Gluten Free Flour Blend is hands-down the best substitute for conventional all-purpose flour in most recipes.   When I need a softer, tender crumb, in a recipe where I would normally use cake flour, I prefer King Arthur Measure For Measure Flour. It has different ratios of flours and starches than the Bob’s Red Mill and produces the more tender result I am looking for. This is also why I do not think it is a good all-around substitute for all-purpose flour in conventional recipes, where it can yield a gummy result.   Using The Right Flour, Correctly   For a deeper dive, read our article Choosing A Low FODMAP All-Purpose Flour.   This recipe will be its best texture if made with King Arthur Measure For Measure Flour, measured correctly, of course. We suggest whisking first to aerate, then dip and sweep with accurate dry measuring cups.   Learn all about accurate volume measuring in this article.