Preheat your oven to 200°C (400°F), fan-assisted. Peel the sweet potato and cut it into even cubes. Toss the cubes in a bowl with the olive oil, a generous pinch of salt, black pepper, and smoked paprika or cumin if desired. Spread them out in a single layer on a lined baking tray without crowding them. Bake for 25–30 minutes, stirring through once at the halfway point, until the edges are caramelized and golden and a fork slides through the center easily. Set aside to cool slightly; they should go into the bowl warm, not hot.