Preheat the oven to 425 degrees F (220 degrees C). Cover a baking sheet with aluminum foil, ensuring the foil goes up the sides of the sheet to catch all the juices.
2
Combine cauliflower, red bell pepper, red onion, olive oil, garlic, fajita seasoning, cumin, and salt in a large bowl; stir until evenly coated. Spread vegetable mixture onto the prepared baking sheet.
3
Roast in the preheated oven for 15 minutes; stir and continue roasting until tender and lightly browned, about 15 minutes more.
