Slice the tempeh into cubes.
Mix soy sauce, olive oil, garlic powder, ginger powder, and maple syrup in a bowl.
Marinate tempeh cubes in the mixture for at least 10 minutes.
Heat a non-stick pan over medium heat.
Add marinated tempeh to the pan and cook until golden brown, about 5-7 minutes.
Remove the tempeh from the pan and set aside.
Add sliced bell pepper, broccoli, and carrot to the same pan.
Stir-fry the vegetables for about 5 minutes until tender-crisp.
Add the cooked tempeh back into the pan and mix well.
Garnish with chopped green onions and serve over rice or noodles.