Place potato slices in a bowl of water while preparing remaining ingredients.
Preheat oven to 350 degrees F (175 degrees C). Spray a 9x13-inch baking dish with cooking spray.
Melt butter in a saucepan over medium heat; cook and stir flour in melted butter for 2 to 3 minutes. Stir in milk until thickened, 4 to 5 minutes more. Add American cheese, mixing until melted. Pour in jarred cheese sauce and cook and stir until smooth.
Spread about 1/2 cup sauce in the bottom of the prepared baking dish. Layer potatoes slices in baking dish, alternating with cheese sauce.
Bake in preheated oven until potatoes are tender, about 90 minutes.

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Nutrition Facts

Per Serving Per 100 g

Amount Per 1 Serving
Calories	274.91 Kcal (1151 kJ)
Calories from fat	125.9 Kcal
		% Daily Value*
Total Fat	13.99g	22%
Cholesterol	42.55mg	14%
Sodium	633.82mg	26%
Potassium	503.57mg	11%
Total Carbs	26.43g	9%
Sugars	9.01g	36%
Dietary Fiber	2.7g	11%
Protein	11.16g	22%
Vitamin C	1.8mg	3%
Vitamin A	1.3mg	43%
Iron	0.9mg	5%
Calcium	319.9mg	32%

Amount Per 100 g
Calories	141.02 Kcal (590 kJ)
Calories from fat	64.58 Kcal
		% Daily Value*
Total Fat	7.18g	22%
Cholesterol	21.83mg	14%
Sodium	325.13mg	26%
Potassium	258.31mg	11%
Total Carbs	13.56g	9%
Sugars	4.62g	36%
Dietary Fiber	1.39g	11%
Protein	5.73g	22%
Vitamin C	0.9mg	3%
Vitamin A	0.7mg	43%
Iron	0.5mg	5%
Calcium	164.1mg	32%

* Percent Daily Values are based on a 2000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.
Find out how many calories should you eat.