Like substituting club soda for baking powder in baked goods or adding brew to make beer bread, fizzy lemon-lime pops' air bubbles create pockets of carbon dioxide in the cake batter and ultimately help the cake rise sans other leavening agents. While some traditional pound cakes use baking powder, Drummond's rendition uses only the flavored soda to achieve its tender crumb and buttery, citrus taste.
When it makes contact with liquid and then heated, baking powder produces carbon dioxide gas and the gas forms bubbles that get trapped in the batter's structure. As the cake bakes, the bubbles expand, causing the cake to rise and become airy. Without baking powder, the batter relies only on mechanical aeration (beating, whisking eggs, creaming butter/sugar), which is not enough to give the same height and softness unless the recipe was designed as a foam cake.
Pancakes are often viewed as a vehicle for butter and syrup or chocolate sauce and fruit, but even the fanciest stack is only as good as its foundation. For perfect, pillowy flapjacks, try swapping in yeast for the baking powder found in most recipes. Yeast, which is commonly used to raise breads, produces a super fluffy, soft texture as well as a subtly tangy depth of flavor that makes your breakfast more exciting.