01 -
Preheat oven to 190°C. Grease a 2-litre baking dish.
02 -
In a small pan, melt the butter over medium-low heat. Sauté diced shallot until softened and translucent, about 4 minutes. Add minced garlic and cook for an additional 30 seconds. Remove mixture from heat.
03 -
Using a box grater or food processor, grate cold baked potatoes with skins intact.
04 -
In a large mixing bowl, mix sour cream, salt, black pepper, 2 cups of the cheddar, and the sautéed shallot and garlic. Gently fold in shredded potatoes to retain their texture, stirring until just combined.
05 -
Gently transfer potato mixture into the prepared baking dish. Evenly sprinkle with remaining cheddar and grated parmesan cheese.
06 -
Bake for 25–30 minutes, until the top is golden brown and bubbling.