01 -
Turn your oven on to 375°F (190°C). Grab a 23×33 cm baking dish and coat it with the butter.
02 -
Slice the peeled potatoes thinly—about 3mm thick. Soak the slices in some cold water to stop them from turning brown.
03 -
In a pot, mix the cream, milk, and garlic. Heat over medium, stirring occasionally, until the edges just start to bubble. Turn it off and move it off the heat.
04 -
Rinse off the potato slices, pat them dry, and layer them in the buttered baking dish. Slightly overlap them like shingles.
05 -
Carefully pour the warm garlic-cream concoction over the potatoes. Spread it out evenly so all slices get coated.
06 -
Distribute the shredded Gruyère and Parmesan cheese over the layered potatoes.
07 -
Add some salt and a good shake of pepper across the top.
08 -
Cover the dish snugly with foil and pop it in the oven for 45 minutes.
09 -
Take off the foil and bake for another 20–30 minutes. The top should get golden and crispy, and the potatoes easily pierced with a fork.
10 -
Pull the dish out of the oven and wait for 10 minutes before digging in.