Sesame Tofu With Broccoli

Name: Sesame Tofu With Broccoli
Ingredients: 1 14-oz. block extra-firm tofu; 1 large head of broccoli (about 1 lb.); 1 scallion; 1 1 piece ginger; 1 garlic clove; ¼ cup tamari or soy sauce; 2 Tbsp. light or dark brown sugar or pure maple syrup; 2 Tbsp. tahini; 2 Tbsp. unseasoned rice vinegar; 1 Tbsp. toasted sesame oil; 1½ tsp. plus ¼ cup cornstarch, divided; 1½ tsp. Diamond Crystal or ¾ tsp. Morton kosher salt, divided, plus more; 1 Tbsp. plus ¼ cup grapeseed oil or vegetable oil, divided; ¼ tsp. freshly ground black pepper; 1 Tbsp. toasted sesame seeds; Steamed white or brown rice (for serving)