Ingredients
3 pounds (1.4 kg) potatoes, thinly sliced
Salt and pepper to taste
9 tablespoons (110 g) all-purpose flour, divided
6 tablespoons (85 g) butter, diced
1 quart (950 ml) whole milk, or as needed
Directions
Step 1
Preheat the oven to 220°C (425°F). Grease a 23x33 cm (9x13 inch) baking dish.
Step 2
Layer 1/3 of the thinly sliced potatoes in the bottom of the greased baking dish and season with salt and pepper. Sprinkle 3 tablespoons of flour on top and dot with 1/3 of the diced butter. Repeat the layering process twice more, then pour in enough milk to fill the dish 3/4 full.
Step 3
Bake in the preheated oven and check every 15 minutes until the milk comes to a boil, which takes about 45-60 minutes. Reduce the heat to 190°C (375°F) and continue baking until the potatoes are tender, which takes an additional 45-60 minutes.