Preheat the Oven:

Preheat your oven to 350°F (175°C).

Prepare the Potatoes:

Boil the peeled and cubed potatoes in salted water until just tender, about 8-10 minutes. Drain and set aside.

Make the Cheese Sauce:

In a saucepan, melt the 4 tablespoons of butter over medium heat.

Stir in the flour and cook for 1-2 minutes to form a roux.

Gradually whisk in the milk and heavy cream, ensuring there are no lumps.

Continue to cook and stir until the sauce thickens, about 5-7 minutes.

Add the salt, pepper, paprika, and garlic powder.

Remove from heat and stir in the cheddar cheese and half of the Parmesan cheese until melted and smooth.

Combine Potatoes and Sauce:

In a large mixing bowl, gently mix the boiled potatoes with the cheese sauce until the potatoes are evenly coated.

Transfer the potato mixture to a greased 9x13-inch baking dish.

Prepare the Topping:

In a small bowl, mix the breadcrumbs or crushed crackers with the remaining Parmesan cheese and 2 tablespoons melted butter.

Sprinkle this mixture evenly over the top of the potatoes.

Bake:

Bake in the preheated oven for 25-30 minutes, or until the top is golden brown and crispy.

Garnish and Serve:

Garnish with chopped parsley before serving.

Serve hot as a side dish to meats or as part of a festive meal.