01 -
Let's get started! First, warm up your oven to 375°F (190°C). This temperature will give us that perfect golden crust while keeping the inside creamy.
02 -
Here comes the magic - melt your butter in a skillet over medium heat, then add those sliced onions. Let them dance in the pan for about 15-20 minutes until they're beautifully golden brown and smelling amazing.
03 -
While the onions are doing their thing, slice your potatoes nice and thin (about 1/8 inch). Toss them in a bowl with the heavy cream, and season generously with salt, pepper, and fresh thyme leaves.
04 -
Time to build! Grab a greased baking dish and create your first layer with half of those creamy potatoes. Top them with half of your caramelized onions. Repeat these layers, then crown it all with that beautiful Gruyère cheese.
05 -
Cover your dish with foil and let it bake for 45 minutes. Then, here's where it gets good - remove that foil and let it bake for another 15-20 minutes until everything's bubbly and golden brown on top.