Cut the potatoes into small wedges, don't peel them. Soak the potatoes in a bowl with cold water for 30 min. Drain using paper towels. Return to a dry bowl. Add all spices. Toss until the potatoes are well coated.
Preheat the oven to 200 C.
Line a baking sheet with parchment paper, transfer the potatoes into one layer, trying not to touch each other. Roast 20-25 min. until lightly golden or fork-tender.
Mash the avocado. Add all ingredients, gently stir to combine.