Mix the vegetable broth, both soy sauces, sugar, pepper, and sesame oil in a small bowl. Stir the cornstarch and water in a separate bowl until smooth.

Heat a large skillet over medium high heat with a quarter cup of water. Add the broccoli and a pinch of salt. Cover and steam for 1 minute until bright green, then cook until the water evaporates. Remove the broccoli from the pan.

Wipe the skillet and heat 2 tablespoons of oil over high heat. Add the sliced mushrooms in a single layer. Sear for 1 minute without stirring to get a golden crust, then flip and cook for 2 to 3 minutes until browned.

Push the mushrooms to one side. Add the remaining oil, chili peppers, garlic, ginger, and green onions to the empty side. Cook until fragrant.

Return the broccoli to the skillet. Pour in the sauce and stir well. Add the slurry and cook until the sauce thickens and coats the vegetables. Serve hot.