Preheat oven to 350°F (180°C).
Wash and dry potatoes, then peel and cut them into halves. Add potatoes and olive oil to a large bowl, stirring to coat evenly. Transfer to a baking sheet and place into the oven. Roast potatoes for 30 minutes or until brown, crispy and fork tender. Remove from the oven and transfer to a medium bowl.
Add mayonnaise, prepared horseradish, lemon juice and lemon zest. Mix well. Transfer potatoes to a serving bowl. Garnish with parsley. Enjoy!