Preheat your oven to 400°F (200°C). Spread the sweet potato chunks on a baking sheet, toss with 1 tablespoon of olive oil and a pinch of salt, then roast for about 40 minutes until tender and fragrant.
Once roasted and cool enough to handle, transfer the sweet potatoes to a large mixing bowl. Mash them thoroughly with a masher or fork until smooth and creamy, adding a pinch of salt and black pepper to enhance flavor.
In a small bowl, combine the breadcrumbs with the dried or chopped fresh sage, melted butter, and minced garlic. Mix until the breadcrumbs are evenly coated and fragrant.
Spread the mashed sweet potatoes evenly in an ovenproof baking dish, smoothing the top with a spatula. Sprinkle the herb- breadcrumb mixture over the surface, pressing lightly so the topping adheres.
Bake in the preheated oven for about 15 minutes until the topping is golden brown and crispy, and the edges of the sweet potatoes start to bubble.
Remove from the oven and let it rest for a few minutes. Serve warm, garnished with additional sage if desired, and enjoy the combination of tender sweet potatoes with crunchy, aromatic topping.
