Preheat your oven to 425°F (220°C).
Prepare a baking sheet by lining it with parchment paper or lightly greasing it.
In a large bowl, combine diced sweet potatoes, olive oil, minced garlic, salt, and black pepper.
Spread the sweet potato mixture in a single layer on the prepared baking sheet.
Roast in the oven for 25-30 minutes, tossing halfway through.
Remove from the oven, and sprinkle with grated Parmesan cheese.
Return to the oven and roast for an additional 5-10 minutes until the cheese is golden brown.
Garnish with chopped parsley, if desired, and serve warm.