Heat a large skilled on high heat. Add 2 Tbsp oil. Add onions in a single layer. Cook until brown on one side then stir. Add zucchini and carrots and cook (without stirring) until browned on one side. Toss everything together and stir until vegetables are tender. Add a tablespoon or two of soy sauce then remove onions and vegetagles from heat and transfer to a platter.
Place skillet back on stove on high heat. Add 2 Tbsp oil. Add broccoli in a single layer. Once it starts to brown, toss and cook until tender. Add 1 Tbsp. soy sauce, stir, then remove from heat and transfer to the platter.
Place skillet back on stove on high heat. Add 2 Tbsp. oil. Add chicken or steak in a single layer (may need to cook in two batches). Don't stir meat until one side is brown. Then stir and cook until meat is done. Add 1-2 Tbsp soy sauce, toss, then remove from heat and transfer to the platter with the vegetables.
Add 2 Tbsp oil and butter to the skillet on high heat. Add rice. Cook and stir for a minute or two. Add vegetables and meat. Drizzle in 1/4 cup soy sauce (add more 1 Tbsp. at a time, if desired). Stir and serve.