Good morning & welcome to our culinary club. You have posed a very interesting question. I sometimes modify a recipe by employing some cornstarch in order to weaken the baked product like soft white dinner rolls & shortbread cookies.
However Cindy I have never heard of anyone employing 50% cornstarch for a wheat flour. I will try to answer your your ??? about the RELATIONSHIP between cornstarch & wheat flour. First off we must examine the important properties of these two ingredients. Wheat flour has GLUTEN in it. And it is also a starch. Cornstarch does not have GLUTEN in it but is also a starch.
SRARCHES require a agent in order to do their thing. That is we need hydration WATER or a liquid then the starches in both of these two ingredients begin to function. Flour is the starch component that holds the structure together with the eggs. Cindy, all I can see is that the cornstarch uses up space in the batter, it doesn’t provide structure. It mainly is employed to produce a cake that
will be as light as a feather. The other three ingredients , FAT,butter, shortening, veg. oil, LIQUIDS, milk, water, fruit juice SUGAR,
honey cornstarch molassis, ete must be in balance with each other without the cornstarch except for the liquids which is required for the starch in the flour as well.
Cindy I hope I did a good job in explaining it to you. I wish you good luck & enjoy the rest of the day young lady.
PS:, I noticed your cake that you posted…excellent work. You are learned & atristically talented as well Cindy.