Preheat your oven to 425°F (220°C).
In a large bowl, toss the cauliflower florets with olive oil, garlic powder, onion powder, smoked paprika, salt, and pepper until evenly coated.
Spread the cauliflower in a single layer on a baking sheet lined with parchment paper.
Roast in the preheated oven for 25-30 minutes, or until the cauliflower is tender and golden brown, stirring halfway through.
Remove the cauliflower from the oven and sprinkle the shredded cheddar cheese and crumbled bacon over the top.
Return to the oven for an additional 5-7 minutes, or until the cheese is melted and bubbly.
Remove from the oven and garnish with sliced green onions, sour cream, and fresh parsley if desired. Serve warm.