Cook the ground pork or chicken: Heat a wok or large skillet over medium-high heat with 1 tablespoon of oil. Add the ground meat and cook until browned, breaking it up with a spatula. Drain any excess fat.

Stir-fry the vegetables: Add another tablespoon of oil to the pan. Add the onion and stir-fry for 1-2 minutes until softened. Add the carrots, celery, and bell pepper (if using) and stir-fry for another 2-3 minutes. Add the snap peas and broccoli and stir-fry for 1-2 minutes more, until they are crisp-tender.

Make the sauce: In a small bowl, whisk together the soy sauce, sesame oil, and white pepper. Add a touch of water if the mixture seems too thick.

Combine and cook: Add the cooked meat and shrimp back to the pan with the vegetables. Pour the sauce over everything and toss to coat. Cook for 1-2 minutes, until the sauce is heated through and the vegetables are fully cooked.