Add baby spinach to a large bowl. Heat 1 tablespoon of avocado oil in a pan over medium-high heat. When the oil is hot, stir fry the onion and red pepper together with a pinch of salt until the onion becomes translucent, about 8-10 minutes. Remove from heat and add to spinach.
Heat another tablespoon of avocado oil in the same pan over medium-high heat and stir fry shiitake mushrooms with a pinch of salt until just beginning to caramelize, about 10 minutes. Remove pan from heat and add mushrooms to the bowl of vegetables.
Heat a final tablespoon of avocado oil in the same pan used for the mushrooms over medium-high heat. Stir fry carrots with a pinch of salt until soft but still tender crisp, about 5 minutes. Remove pan from heat and add carrots to other cooked vegetables.
Drain the noodles into a large strainer and rinse with warm water for several minutes. Drain well.
In the empty pan used for cooking vegetables, add noodles and cook over medium high heat, stirring with tongs until moisture has evaporated and the noodles are hot, about 5 minutes. Then add garlic and cook until fragrant, another two minutes, stirring frequently. Add all remaining sauce ingredients and cook, stirring often until the liquid is absorbed, another 5 minutes.
Add cooked noodles to the bowl of vegetables and mix well. Season with salt and sprinkle with pine nuts on top.