Mongolian Beef & Broccoli

In a large skillet over medium-high heat, heat 1/4 cup oil. Toss beef with cornstarch. Cook until crispy, 2 minutes per side. Transfer to a plate and drain fat. Add remaining teaspoon oil to skillet. Add garlic and ginger and cook until fragrant, 1 minute, then add hoisin sauce, soy sauce, brown sugar, and water. Bring to a simmer and let thicken, 4 to 5 minutes, then add broccoli. Cover and cook until tender, about 3 minutes, then return beef to skillet and stir until completely coated in sauce. Garnish with sesame seeds and serve over rice.