Potatoes Romanoff

I know I have a multitude of recipes at the touch of a button. Thanks to blogs, Pinterest, The Food Network etc. there is plenty to choose from. But I still enjoy opening the mailbox and seeing a new cooking magazine. I have limited the number I receive--recipe overload is real. This year I chose to subscribe to Cook's Country. I like the large format, the easy meals and I like to know why recipes work and Cooks gives me the information I enjoy. So this year you will see favorites from this magazine on my blog.
I'm always looking for a good potato recipe. We like potatoes in many forms. This recipe did not disappoint. It was yummy and worth the work for a special Sunday Dinner. You can also make this the day before, a plus for a busy cook.

Potatoes Romanoff
3 pound russet potatoes, peeled and cut into 1/2 inch pieces
1 1/2 teaspoons salt
1 1/4 cup sour cream
4 ounces cream cheese, softened
1 tablespoon cornstarch
1/2 teaspoon pepper
1 3/4 cups chicken broth
4 scallions, white parts minced, green parts sliced thin on the bias
6 ounces sharp cheddar cheese, shredded (1 1/2 cups) I like Tillimok

Toss potatoes with salt in a large bowl, cover and microwave until tender about 15 minutes. Stir once.
Whisk sour cream, cream cheese, cornstarch and pepper in a large bowl until combined. Whisk in chicken broth and scallion whites until incorporated. Fold in hot potatoes in two additions. Pour mixture in an 8 inch square baking dish. Sprinkle with cheddar cheese. Place dish on rimmed baking sheet and bake on upper middle oven rack for 15 to 20 minutes in a 425 degree oven. Casserole should be bubbling and cheese slightly brown. Let cool for 20 minutes. Sprinkle green onions on top. Serves 6 to 8.
You can make the casserole ahead and bake it at 425 for 30 to 35 minutes.