Fill a stockpot with 5 quarts of water and bring it to a boil.
Slice the leaves off from the bok choy stalks. Stack the leaves and slice them into strips. Slice the stalks into pieces about 1/4 inch thick.
Add linguini to the boiling water, along with the salt.
When linguini is just about al dente, add the bok choy to the salted water, and let it cook along with the pasta, for another 2 to 3 minutes.
Reserve about 1 cup of the cooking water, and drain the pasta and bok choy into a colander.
In a saute pan, heat the oil, and add the Chinese Five-spice powder, ginger, and chili paste, and stir for about 30 seconds until fragrant.
Add the garlic base and water mixture, and stir to combine everything.
Let the mixture come to a boil, and then reduce the heat to medium low and simmer for about 5 minutes to thicken.
Add the tofu and let it absorb the liquid for 2 minutes.
Add the carrots, mushrooms, and linguini/bok choy mixture.
Stir to combine and loosen the noodles.
If desired, add the tofu and stir to combine.
Reduce the heat to low, and add any extra pasta water if the noodles need more sauce.
Taste and season with pepper and soy sauce.
Serve immediately
