Heat oven to 325 degrees and generously butter a shallow gratin dish. Heat butter in a large saucepan over medium-low heat. Once the butter is melted, add onion, shallot and garlic and season with salt and ground pepper. Cook until translucent, ~10 minutes.
Add the flour and cook until golden brown, 2-3 minutes.
Stir in light cream and thyme and simmer on medium-low for 5-10 minutes.
Meanwhile, using a mandoline, slice the potatoes and apples thinly.
Once the cream mixture is warm, turn off the heat and add the blue cheese and combine. Season with Worcestershire sauce, salt & ground pepper and set aside.
Transfer potatoes and apples to the prepared baking dish and spread evenly.
Pour the cream mixture over the potatoes and apple and spread the thyme springs across the top.
Cover the dish with foil and bake until the potatoes are tender, about 80 minutes.
Uncover the gratin dish and remove the thyme springs and place under the boiler until brown.
Once brown, remove from the oven.
Serve warm with your favorite protein and enjoy, cheers 🥂!
