01 -
Make sure your casserole dish (8x8 inches) is completely greased.
02 -
Lay the potatoes evenly across the dish.
03 -
Combine the cream, milk, dry mustard, nutmeg, pepper, and salt in a saucepan.
04 -
Warm the mixture over medium-high heat, stirring constantly until it’s just shy of boiling (about 5-10 min).
05 -
Turn down the heat, toss in the cheese, and stir until it melts completely.
06 -
Drizzle the cheesy mixture all over the potatoes.
07 -
Give it a few minutes to cool off slightly.
08 -
Dot the top with the butter slices.
09 -
Dust the surface with a little paprika.
10 -
Cover it tightly with plastic film.
11 -
Let it rest in the fridge for 12 hours or overnight.
12 -
Preheat your oven to 350°F.
13 -
Put the dish in the oven and bake it, uncovered, for about 45 minutes.