Potato, Onion, & Rosemary Casserole

This potato casserole keeps it focused: thinly sliced russets, butter-softened onions perfumed with fresh rosemary, and a cup of half-and-half poured over the top before baking. No cheese, no breadcrumbs, no distractions. The potatoes, cream, and rosemary-onion combination stand on their own.

Cooking the onions first for a full 10 minutes until they’re soft and starting to brown is the step that makes this more than basic scalloped potatoes. Those caramelized onions bring a sweet, savory depth between each potato layer that you don’t get from raw onion slices.

Two tablespoons of fresh chopped rosemary is a generous amount, and the long baking time mellows it into something aromatic rather than overpowering. The half-and-half seeps down through the layers during the covered hour of baking, and the final 20 minutes uncovered gives the top a golden, slightly crispy crust.

Kitchen Tips

• Slice the potatoes thin and even. A mandoline is ideal. Uneven slices mean some are crunchy while others are overcooked mush.
• Don’t skip the foil for the first hour. Covering traps steam that cooks the potatoes through. Uncovering too early dries the top before the center is tender.
• Let it rest 10 minutes before cutting. The casserole sets up slightly as it cools, making cleaner wedges.

Variations

• Gruyere topping: Sprinkle shredded Gruyere over the top before the uncovered baking phase for a bubbling, cheesy crust.
• Garlic addition: Add 3 to 4 minced garlic cloves with the onions for a more robust flavor base.