First, know your players. All-purpose flour is the workhorse. It’s rugged. It builds chewy cookies and sturdy breads. Cake flour is the delicate diva. It’s softer than a kitten’s ear. It makes cakes tender and cloud-like.
The secret? Protein. All-purpose has about 10-12%. Cake flour has a meager 6-8%. Less protein means less gluten. Less gluten means less toughness. It’s literally a fluffier math problem.