The Secret Weapon Ingredient For Reheatable Mashed Potato Casserole

From holiday homestyle meals to summer barbeques, mashed potatoes bring people together. And what better way to serve them than in a giant casserole dish, steaming hot and loaded with extras like cheese, pulled pork, corn, bacon, gravy — the list of tasty toppings goes on.

You might think the party's over once the lingering guests finally head out, and you're surrounded by half-full dishes and pans, but now the real fun begins. Any dinner host knows that the best thing about parties is the leftovers, and here's where that secret weapon ingredient saves the day. For fluffy, moist, and wonderfully reheatable mashed potato casserole, just add sour cream.

Sour cream not only adds a sharp, tangy flavor to potatoes, but its dairy density makes them super rich, yet light. While other dairy products also enhance the dish, the complex processes of fermentation, homogenization, emulsification, and pasteurization make sour cream flavorful, smooth, safe, and perfect for pairing with mashed potato casserole.

After spending a night or two in your fridge, mashed potatoes can turn gummy and gritty, and even if they're yummy enough to eat cold, properly heating them makes for a much softer texture. Reheating mashed potatoes with dairy products moistens the potato starch in a process called reverse retrogradation. This helps give previously unappetizing leftovers a new, delicious life on your plate.

Whether microwaving, stovetop steaming, or baking, adding extra dairy is key. Mashed potato staples like butter, milk, heavy cream, and cream cheese also produce great casseroles, but sour cream adds the perfect amount of moisture and flavor and produces the best result when reheated. Plain old butter and cream yield dry, bland results while mash made with cream cheese is a bit too dense. Lying somewhere between the two in terms of density and moisture, sour cream is the clear winner for taste and texture.

Both Martha Stewart and Ina Garten use sour cream combined with milk and butter for mashed potatoes, and we'd all love a seat at their dinner tables. So next time you host a big crowd, try blending sour cream into your mashed potato casserole recipe. Who knows, it might taste even better on the second day.