Preheat oven to 450° with rack in lowest position.
Line a baking sheet with foil.
Whisk together canola oil, sesame oil, soy sauce, garlic, salt, and pepper flakes.
Toss broccoli florets and stems with oil mixture and transfer to prepared baking sheet.
Roast broccoli on bottom rack until crisp-tender, 10–12 minutes.
