In a small bowl, marinade your sliced shiitake mushrooms with 1 garlic clove minced, 1 tsp cane sugar, ¼ tsp black pepper and 2 tsp soy sauce. Set aside and marinade for 10 minutes.
In a large pot of boiling water, blanch your spinach for 30 seconds no more. Remove the spinach with a slotted spoon reserving the hot water for the noodles. Rinse with cold water to stop cooking. Squeeze out the excess water. Place into a large mixing bowl and season with 1 tsp soy sauce, and 1 tsp sesame oil and mix.
Boil your sweet potato noodles for 7 minutes until soft and chewy. Drain and add to your large mixing bowl. Season the noodles with 2 tsp sesame oil, 1 teaspoon soy sauce, and 1 teaspoon sugar. Mix well.
Now fry your vegetables separately until they are cooked and soft. Start with your shiitake mushrooms, followed by white button mushrooms, then carrots, bell peppers, and lastly onion. As you finish cooking each vegetable element, add it to the large mixing bowl.
Finally, once all your ingredients are cooked and in the mixing bowl, add: 1 minced garlic, 1 tbsp soy sauce, 1 tbsp sugar, ½ tsp black pepper, and 2 tsp sesame oil and mix well. Serve and enjoy!