Preheat and prep — Preheat your oven to 220°C / 425°F and line a rimmed baking sheet with parchment. A hot oven gives sweet potato cubes a fast, high-heat roast so their edges caramelize and develop concentrated sweetness rather than steaming and staying soft.

Season and toss the sweet potatoes — In a large bowl, toss the 800 g cubed sweet potato with 2 tbsp (30 ml) olive oil, 1/2 tsp salt and 1/4 tsp freshly ground black pepper. Spread in a single layer on the prepared baking sheet, leaving small gaps between cubes so air circulates and they brown evenly. Resist crowding — if the pan’s crowded they will steam instead of caramelize.

Roast the sweet potatoes — Roast on the middle rack for 25–30 minutes, tossing once at 12–15 minutes, until edges are deep golden and centers are tender when pierced. High heat creates Maillard browning which gives the sweet potatoes a nutty, caramelized flavor that stands up to the beans and salsa.

Make the mango–jalapeño salsa — While the potatoes roast, combine the diced mango (360 g), finely chopped jalapeño (2, seeded if you prefer milder heat), 80 g finely diced red onion, and most of the chopped cilantro (reserve a tablespoon for garnish) in a bowl. Add the juice of 2 limes (about 60 ml) and 1/4 tsp salt; stir and taste. Let the salsa sit at room temperature for at least 10 minutes so the lime brightens the mango and the jalapeño’s heat mellows and infuses the mixture.

Warm and spice the black beans — Heat 1 tbsp (15 ml) olive oil in a medium skillet over medium heat. Add the 1 tsp smoked paprika and 1 tsp ground cumin and toast for 20–30 seconds, stirring constantly; this 'blooming' step wakes up the spices and releases essential oils for deeper flavor. Add the cooked black beans (560 g). Use a potato masher or back of a spoon to press some of the beans — leaving plenty whole — so you have a mix of creamy and textured beans. Add 1/2 tsp salt and a few grinds of black pepper, and cook for 4–6 minutes until the beans are warmed through and slightly reduced.

Adjust texture and seasoning — If the beans seem dry, add 1–2 tbsp water and stir; if you like a saucier filling, finish with a squeeze of lime. Taste and adjust salt, pepper or an extra pinch of cumin/smoked paprika to balance flavors. Slightly mashed beans cling to the sweet potato while retaining pleasant bite.

Warm the tortillas — Heat a dry cast-iron pan or skillet over medium-high heat. Working in batches, warm each corn tortilla about 20–30 seconds per side until lightly charred in spots and fragrant; this develops a toasty aroma and improves pliability. Stack warmed tortillas in a clean kitchen towel to steam for 2–3 minutes so they stay soft and easy to fold.

Assemble the tacos — Build each taco starting with 1/2 cup (about 70–75 g) of the spiced black beans, then a generous spoonful of roasted sweet potato cubes, and finish with 2–3 tablespoons of mango–jalapeño salsa. Sprinkle reserved cilantro and freshly ground black pepper. Serve with lime wedges and optional garnishes.

Serve immediately — Tacos are best eaten right away while the filling is warm and the tortillas are soft. If you must hold them, keep assembled tacos covered loosely with foil and a damp towel to prevent drying.