Preheat the oven to 425°F (220°C). Line a large baking sheet with parchment paper for easy cleanup.
In a large bowl, combine the diced sweet potatoes and sliced sausage. Drizzle with olive oil, then sprinkle with garlic powder, onion powder, smoked paprika, salt, and pepper. Toss until everything is evenly coated.
Spread the sweet potato and sausage mixture in a single layer on the prepared baking sheet.
In a small bowl, whisk together the honey, minced garlic, soy sauce, apple cider vinegar, and red pepper flakes (if using).
Drizzle half of the honey garlic sauce over the sausage and sweet potatoes. Reserve the other half for later.
Bake in the preheated oven for 25-30 minutes, stirring halfway through, until the sweet potatoes are tender and the sausage is browned.
Remove from the oven and drizzle the remaining honey garlic sauce over the dish. Toss to combine.
Garnish with chopped parsley before serving.