Step 1

Preheat oven to 350f

Step 2

Wash and coarsely chop the potatoes, and place them into a large bowl with the rosemary. Pour the olive oil on top of the potatoes and toss to coat.

Step 3

Spread the potatoes in a single layer on a heavy rimmed baking sheet.

Step 4

Roast the potatoes for 35-40 mins, or until they are easily pierced with a fork. Turn the potatoes at least once.

Step 5

Remove potatoes from the oven and transfer to a heatproof bowl.

Step 6

Mash the potatoes well. Add the onions, cheddar, sour cream and 1/2 cup of milk. You may need to add more milk to get to the creamy consistency desired, it just depends on how large your potatoes were and how dry they got in the oven.

Step 7

Salt and pepper to taste.

Step 8

Transfer to a baking dish and bake at 350 for 20-25 minutes.

Step 9

Serve hot.