All-Purpose Flour with Cornstarch (Best Option)
1 cup cake flour = 1 cup all-purpose flour minus 2 tablespoons + 2 tablespoons cornstarchCake flour has a lower protein content (about 7-8%) compared to all-purpose flour (10-12%), which contributes to a softer, finer texture. By replacing 2 tablespoons of all-purpose flour with cornstarch per cup, the overall protein content is reduced, mimicking cake flour's properties. Cornstarch also helps to prevent clumping and adds silkiness.
For best results, sift the mixture before adding to the smoothie to ensure even dispersion. Avoid over-blending to prevent activating gluten, which can cause a slightly chewy texture.
Compared to pure cake flour, this substitute maintains the smooth mouthfeel and prevents the smoothie from feeling gritty or heavy, preserving the intended light texture and neutral flavor.