Baked Cheesy Potatoes

Preheat oven to 350°F. Coat a 9-by-13-inch baking dish with cooking spray.

Heat oil in a large skillet over medium heat. Add onion and cook, stirring, until starting to soften, about 3 minutes. Sprinkle flour over the onion and cook, stirring, for another minute. Increase heat to medium-high and whisk in broth, milk, salt and pepper, making sure there are no lumps. Bring to a simmer and cook, stirring, until thickened, 3 to 4 minutes. Remove from heat and stir in Cheddar, sour cream and Parmesan. Fold in hash browns.

Transfer the mixture to the prepared baking dish and sprinkle with crushed potato chips. Bake until golden and bubbling around the edges, 40 to 45 minutes. Let rest for 10 minutes before serving.