Cut your broccoli into florets, peel the stalks and slice into thin coins. Set aside.
Mix garlic, broth, soy sauce, cornstarch, brown sugar, sesame oil, and fish sauce in a bowl. Set aside.
Heat canola oil in a large skillet. When oil is hot, add the broccoli. Cook 4 minutes, stirring continuously, until the broccoli is brown in places. Add 1/2 cup water, cover, and cook for an additional 4 minutes, until the broccoli is starting to get tender.
Stir in the sauce, cook for 2 more minutes until the sauce starts to thicken and the broccoli is cooked to your desired tenderness. Garnish with scallions if you'd like.