Heat the oven: Preheat to 425°F (220°C). Line a large baking sheet with parchment for easy cleanup.

Slice the sweet potatoes: Cut into 1/2-inch-thick rounds for sturdy bites. Thinner slices can burn or get floppy.

Season and roast: Toss rounds with 1–2 tablespoons olive oil, 1 teaspoon salt, 1/2 teaspoon pepper, and a pinch of cumin and smoked paprika if using. Arrange in a single layer. Roast 20 minutes, flip, then roast 10–15 minutes more until tender with browned edges.

Make the avocado topping: In a bowl, mash avocados with 1–2 tablespoons lime juice, a pinch of salt, and a little lime zest. Keep it a bit chunky.

Season the beans: Toss black beans with a drizzle of olive oil, a squeeze of lime, a pinch of salt, and a dash of cumin or chili powder. Stir in the red onion or scallions.

Chop cilantro: Roughly chop leaves and tender stems. Set aside.

Assemble: Once rounds are roasted and slightly cooled, top each with a spoonful of avocado, a few black beans, and a sprinkle of cilantro. Finish with more lime zest and a crack of black pepper.

Optional cheese: Add a light shower of cotija or feta. For heat, add pickled jalapeños or a few drops of hot sauce.

Serve: Plate warm or at room temperature. Add lime wedges on the side for extra brightness.