Peel and slice the potatoes thinly, about ⅛ inch thick. Try to keep them as even as possible so they cook at the same rate. This step may seem simple, but it’s the foundation of the entire dish.

In a saucepan, melt the butter over medium heat. Add the chopped onions and cook until they become soft and slightly translucent. Then add the garlic and cook just until fragrant.

Sprinkle in the flour and whisk continuously for about a minute. Slowly pour in the milk and cream, whisking as you go to avoid lumps. Let it cook until it thickens slightly into a smooth, velvety sauce.

Add salt, pepper, and paprika. Taste the sauce — this is your moment to adjust flavors. It should be rich, slightly savory, and comforting.

Grease your baking dish lightly. Add a layer of sliced potatoes, then pour over some sauce. Repeat the layers until everything is used. Finish with cheese on top if you’re using it.

Cover the dish with foil and bake at 180°C (350°F) for 50 minutes. Then remove the foil and bake for another 30 minutes until the top is golden and bubbling.

This step is often overlooked, but it’s important. Let the dish sit for about 10 minutes before serving. It allows the sauce to settle and thicken beautifully.