It’s for any type of rising batter or dough that results in a rounded ball shape while cooking. Commonly used for ableskiver, okonomiyaki, donuts, cake pops, cornbread, etc. Ableskiver is a sweet danish pancake dusted with powdered sugar, usually served with a berry jam or syrup for breakfast or dessert/snack. Okonomiyaki balls are made in Japanese food stalls, a savory seafood/bacon/cabbage egg batter with a dark soy based sauce and mayo. Most pour the batter in to rim, then keep adding more batter/ingredients while turning and flipping the cooking ball Using a chopstick, skewar etc to do the flipping. But your set up looks like you can add batter then use the second mold on top to form the round ball as it rises, or flip the whole thing midway as it cooks. Youtube has got to have videos on this...