Preheat the oven to 425°F and line a large baking sheet with parchment paper.
In a large mixing bowl, combine the broccoli and cauliflower florets.
Drizzle the olive oil over the vegetables and toss to coat evenly.
Sprinkle the garlic powder, onion powder, smoked paprika, salt, and black pepper over the vegetables. Toss again until the seasonings are evenly distributed.
Spread the vegetables in a single layer on the prepared baking sheet, ensuring they are not overcrowded.
Roast in the preheated oven for 20-25 minutes, flipping the vegetables halfway through, until they are tender and lightly browned at the edges.
Remove the baking sheet from the oven and let the vegetables cool for 5 minutes before serving.