Low-fat scalloped Potatoes

2 T unsalted butter, plus more for dish
Kosher salt
3lbs yukon gold potatoes, peeled and think sliced
2 T flour
1 cup low fat milk at room temp
1 cup whole milk at room temp
Fresh pepper
1/2 t nutmeg
1/4 cup grated Gruyere cheese

350 degrees.
Lightly butter baking dish. Bring large pot of salted water to a boil, add potatoes and cook until just tender. Drain and return to pot.
Melt 2 T butter in a saucepan over medium heat. Stir in flour to make a paste. Stir until the past puffs slightly. Add both milks gradually. Whisking constantly, until thick. Remove from heat and whisk in 1/2t pepper, 1.5 t salt and nutmeg. Pour sauce over the potatoes and gently toss to coat.
Transfer the potato mix to dish and sprinkle with Gruyere. Bake until heated through, 10mins. Then switch to broil and boil until browned (5mins)
Let rest for 10mins before serving.