3 Large Potatoes, Peeled And Diced

4 Tablespoons Unsalted Butter

1/4 Cup All-purpose Flour

1 Cup Whole Milk

4 Large Eggs, Separated

1/4 Teaspoon Salt

1/4 Teaspoon Black Pepper

1/4 Teaspoon Cream Of Tartar

Step: 1

Preheat Your Oven To 375°f (190°c). Grease A 9-inch Baking Dish With Butter Or Cooking Spray.

Step: 2

Boil The Diced Potatoes In Salted Water Until They Are Fork-tender. Drain And Set Aside.

Step: 3

In A Medium Saucepan, Melt The Butter Over Medium Heat. Add The Flour And Whisk For 1-2 Minutes Until The Mixture Is Smooth.

Step: 4

Gradually Whisk In The Milk, Salt, And Black Pepper. Cook For 3-5 Minutes, Whisking Constantly, Until The Mixture Thickens.

Step: 5

Remove The Saucepan From The Heat And Whisk In The Egg Yolks One At A Time Until The Mixture Is Smooth.

Step: 6

In A Separate Bowl, Beat The Egg Whites And Cream Of Tartar Until Stiff Peaks Form.

Step: 7

Gently Fold The Egg Whites Into The Potato Mixture. Pour The Mixture Into The Prepared Baking Dish. Sprinkle The Grated Cheddar Cheese On Top.

Step: 8

Bake For 20-25 Minutes, Until The Soufflé Is Puffed And Golden Brown.

Step: 9

Serve Immediately, Garnished With Chopped Parsley Or Chives If Desired.