Homemade Blueberry Upside-down Cake is unbelievably good. Blueberries and a caramel glaze ooze down into the tender yellow cake making it moist and decadent. This cake recipe has quickly become one of my all-time favorites! My Homemade Blueberry Upside-down Cake starts with a tender yellow cake made with all-purpose flour, vegetable oil, eggs, and sugar. It's based on