Preheat oven to 220°C/425°F. Julienne beetroot and transfer to a mixing bowl. Salt to taste and set aside to marinate.
Peel and chop garlic. Finely chop oregano and rosemary. Add olive oil, oregano, rosemary, chopped garlic, cane sugar, and paprika powder to a bowl and stir to combine.
Halve sweet potatoes and brush with marinade. Transfer sweet potatoes to a parchement-lined baking sheet and bake at 220°C/425°F for approx. 15 min., or until fork-tender.
Add pine nuts to a small frying pan over medium heat. Toast for approx. 2 – 3 min., or until golden brown. Add mayonnaise, sour cream, and truffle oil to a small mixing bowl and stir to combine. Season with salt and pepper to taste.
Remove sweet potatoes from oven and mash the inside with a fork. Top with mayonnaise, marinated beetroot, and toasted pine nuts. Garnish with chopped chives and enjoy!