I'm making an Fine Cooking recipe for cinnamon rolls that uses a biscuit dough, so no yeast, no proofing.
Oof...this feels like a bit of a bad sub to me. How are these supposed to rise? Because typically, you want cinnamon rolls to rise and form gluten, and cake flour has a lower protein (gluten) content than AP flour and won't give you the structure, rise or texture you want
Do you have bread flour? You could do a blend of cake flour and bread flour to approximate AP flour.
Hardlikearmour is correct. A Pearson's square, a formula used to calculate the blend of two ingredients required to produce a third which is a blend of both. yields exactly 50% bread flour and 50% cake flour to achieve AP flour. Cake flour isn't going to contain enough gluten (the protein in flour) to hold your rolls together, even though the aren't a yeasted dough. Gluten is formed when the flour(s) come in contact with water and are mixed, causing their long strands to relax somewhat and hold together nicely when your dough rises in the oven.