Preheat stove to 400°F | 200°C. Delicately oil a 9 x 13-inch heating container with cooking oil shower; put in a safe spot.
Dissolve spread in a medium-sized skillet/pot. Add the garlic and sauté until only fragrant (around 1 moment). Speed in the flour; keep on cooking while at the same time whisking (or blending) for at any rate 2 minutes.
Decrease heat down to low; continuously race in 4 cups of the milk (about ¼ cup at a time), whisking between every expansion to join. Heat to the point of boiling until starting to thicken. Mix in the bullion powder, salt (if necessary), and pepper. Put in a safe spot.
Organize a layer of potatoes over base of arranged dish. Pour half of the cream sauce over the potatoes, at that point top uniformly with half of the mozzarella cheddar, and half of the Parmesan cheddar. Mastermind the leftover potato cuts over the cheddar, the excess rich sauce, and the excess cheeses.
Cover firmly with aluminum thwart and prepare for 40 minutes until potatoes are simply delicate. Eliminate foil; cook for a further 30 minutes or until top is brilliant and the sauce is gurgling. For a crispier top, cook (or barbecue) on medium warmth for 2-3 minutes until cheddar is fresh.