Preheat your oven to 180°C (350°F) and lightly butter a baking dish to prevent sticking.
Using a mandoline slicer, thinly slice the potatoes to about 3mm thickness, ensuring even slices for uniform cooking.
Melt the butter in a saucepan over medium heat, then whisk in a bit of flour to create a roux. Cook and whisk until the mixture turns golden, about 2 minutes, filling your kitchen with a warm, toasty aroma.
Gradually pour in the milk while whisking continuously, bringing the mixture to a gentle simmer. Once thickened, stir in the grated cheese, smoked paprika, and season with salt and pepper, creating a smooth, cheesy sauce.
Spread a thin layer of the cheese sauce on the bottom of your prepared baking dish. Arrange a layer of potato slices over the sauce, then spoon more sauce over these slices, repeating until all potatoes are layered, ending with a generous pour of sauce on top.
Cover the dish tightly with foil and bake for 40 minutes, allowing the potatoes to become tender and the flavors to meld beautifully.
Remove the foil and sprinkle the breadcrumbs along with some extra cheese over the top. Return to the oven and bake uncovered for another 15 minutes, until the top is golden and bubbling with a crispy crust.
Once baked, let the dish rest for a few minutes to settle. Then, serve warm and enjoy the rich, smoky, cheesy layers with a crispy topping.
