Step 1

Preheat oven to 375 F degrees. Grease a baking dish and set aside.

Step 2

Clean leeks and cut them into small chunks.

Step 3

Place a non-stick skillet over medium-high heat and add oil. Once hot, add leeks.

Step 4

Cook until leeks become slightly soft, about 3-4 minutes. Set aside.

Step 5

Cook potatoes until tender. Add them to a large bowl. Then add butter and mash until combined.

Step 6

Add milk and mix until combined. Fold lees and parmesan cheese into mashed potatoes. Mix to incorporate.

Step 7

Pour the mixture into the baking dish and bake for 30 to 40 minutes or until cooked through. Serve and enjoy!