Cheese, Potato and Smoked Sausage Casserole

Ingredients
3 cups peeled and cubed russet potatoes, boiled until tender but not mushy.
1 lb. thinly sliced smoked sausage*, boiled until tender but not mushy
4 tablespoons butter
4 tablespoons flour
2 cups half and half or milk
Salt and pepper to taste
1/2 lb. Velveeta cheese, cubed
1/2 cup grated sharp cheddar cheese
1/4 teaspoon smoked paprika

Instructions
In a large skillet over medium-low heat, sauté sausages with 1-2 tablespoons of olive oil, turning and stirring until they have browned a bit.
Lightly spray a 9×13? baking dish with non-stick cooking spray. Transfer the cooked potatoes and sausage to the baking dish, stirring just until evenly distributed.
Increase the heat to medium and add the butter to the pan. When it has melted, whisk in the flour. Let cook for about a minute, whisking constantly, to remove the flour taste. Slowly add half and half, 1/4-1/2 cup at a time, whisking constantly until evenly incorporated. Continue cooking until thickened.
Stir in Velveeta, paprika, salt and pepper, stirring occasionally until completely melted and the sauce is smooth.
Pour cheese sauce evenly over potatoes and meat. Sprinkle grated cheese evenly over the top.
Bake at 350 degrees for 35-45 minutes, or until potatoes are fork tender and the casserole is golden on top.