Wash and peel all of your russet potatoes. Slice them into very thin round circles now. Try to make them all the same thickness.

Layer half of the potatoes in the dish. Sprinkle some salt and pepper over the top. Make sure the layer is nice and flat.

Melt the butter in a saucepan over heat. Stir in the flour using your metal whisk. Cook it for one minute until it bubbles.

Slowly whisk in the milk and heavy cream. Add the minced garlic to the liquid mixture. Simmer until the sauce starts to thicken up.

Pour half of the sauce over the potatoes. Add the rest of the potato slices now. Pour the remaining sauce over the final layer.

Cover the baking dish with the aluminum foil. Bake it in the oven for thirty minutes. This softens the potatoes with trapped steam heat.

Remove the foil after the thirty minutes pass. Bake for twenty more minutes without the cover. The top should be golden and very bubbly.