Potatoes Au Gratin (Homemade)

8.5 cups sliced potatoes
1-1/2 cubes butter (3/4 cup)
3/4 cup flour
2 cups milk
2 cups cream
2 cups chicken broth plus 3 chicken boullion cubes added
White pepper to taste
Cheddar cheese to top

Cook potatoes in boiling salted water until partially done, 3-5 minutes, and drain. Place potatoes in a 13x9 dish. Melt butter in a saucepan and stir in flour to make a smooth paste. Add the milk, cream, and chicken broth and cook, stirring constantly, until thickened. Add pepper and pour the mixture over the potatoes. Bake at 350 for 45 minutes, add the cheese on top and bake for an addition 4-5 minutes.