Choy sum (Chinese vegetable stir-fry) (vegan)

A choy sum stir-fry is among the best known Chinese dishes in the West, being a staple on menus of Chinese-American restaurants and Asian take-out joints. While traditional Chinese cooks may question how authentic the dish is in the US and Western Europe, it's definitely a crowd favorite. I can understand both stances, since I care about authenticity as well, but I know that regular folks just want their delicious food sometimes, and don't care so much about its origins. 
I decided to research the recipe and try to make the most authentic Choy Sum recipe that can be made outside of its native region, and this was the result.
Recipe source: mainly here.

Last year: nothing.
Two years ago: nothing.
Three years ago: nothing.
Four years ago: Vegan raspberry, cocoa and coconut marbled loaf cake (vegan).
Five years ago: Indonesian potato and spinach curry (vegan).
Six years ago: Bouneschloupp (Green bean and ham soup) (Luxembourgian).
Seven years ago: Crispy pizza crust (vegan).
Eight years ago: Pickled red onions and Linguine alla matriciana with zucchini.



Ingredients (serves 2):

• 2 small carrots, sliced
• 1 cup broccoli florets, chopped
• 1/2 cup Chinese cabbage leaves (bok choi), chopped
• 1/2 red bell pepper, cut into strips
• 1 cup wood ear mushrooms, sliced 
• 1 cup water chestnuts, sliced
• 1 cup fresh mushrooms of any kind, sliced
• 2 apio celery stalks, thinly sliced
• 2-3 stalks of green onion, chopped
• 100 ml water

For the sauce:

• 1 thumb-sized piece of ginger, minced
• 3 garlic cloves, minced
• 2 tablespoons soy sauce
• 1 teaspoon roasted sesame oil
• 1 tablespoon Chinese red wine vinegar
• 1/2 teaspoon corn starch

Put all the veggies and the water in a wok and place them over high heat. Cook, stirring, until they are all cooked but not mushy. The vegetables should still have a bit of bite to them.

After about 5-7 minutes, they should reach that stage and most of the water should be evaporated. Mix the ingredients for the sauce and add them to the wok. Stir energetically until the sauce thickens and coats the vegetables, about 1-2 minutes.

Remove from the heat and transfer to serving bowls. It's done, dig in! :)