Proof is in the... filling. If you’ve ever picked up a box of Bisquick, you’ve likely seen one of its “impossibly easy” recipes printed on the box—dishes ranging from sweet pies to savory casseroles.

It features a genius secret ingredient. Buttermilk is one of my favorite ingredients. I love its creaminess and punchy acidity, which work well in both savory and sweet applications. I’ve never used ...