Season the flank steak with garlic powder, onion powder, smoked paprika, salt, and pepper. Rub with olive oil and marinate for at least 15 minutes.
Prepare the corn by spreading it on a baking sheet, drizzling with olive oil, and seasoning. Roast in a preheated oven at 400°F for 15-20 minutes.
Make the cilantro cream sauce by mixing sour cream, cilantro, and lime juice. Adjust seasoning as needed.
Assemble the bowl with a base of cooked brown rice or quinoa, topped with steak, roasted corn, avocado, cherry tomatoes, and cilantro cream sauce.