Preheat the oven to 180C.
In a large casserole dish, rub the softened butter evenly across on the base and up the sides.
Peel the potatoes then slice thinly, using a mandolin if you have one. If not, use a sharp knife for even thin cuts.
Arrange some of the potato slices in a single layer in the bottom of the dish, overlapping each piece slightly.
In a large bowl, combine the onion, garlic, 130g Parmigiano Reggiano, thyme, salt and pepper.
Sprinkle a third of the cheese mix over the potato layer.
Repeat the layering process twice more, ending with a layer of potato on top.
Pour the double cream over the potatoes, filling the spaces.
Sprinkle the remaining Parmigiano Reggiano over the top and season with salt and pepper.
Bake for 90 minutes, until the top is golden brown, and the potatoes are soft.
Dig in while they are hot, before they are all gone!
Serves: 4
Preparation: 30 mins
Cooking: 90 mins
700g Albert Bartlett Original Rooster Potatoes
1 tbsp unsalted butter, softened
1 onion, finely chopped
3 garlic gloves, minced
160g Parmigiano Reggiano, grated
1tsp fresh thyme
250ml double cream
½ tsp sea salt
½ tsp pepper