Cut zucchini into noodles using a spiralizer fitted with the large shredding blade. Set aside.
Combine 1/4 cup broth, onion, and tomato paste in a large saucepan over medium heat. Cook until onion begins to soften, about 3 minutes. Add tomato, mushroom, garlic, oregano, thyme, tarragon, and marjoram. Cook until the mushroom just begins to soften, about 3 minutes more.
Stir veggie meat, spinach, and remaining 1/4 cup broth into the pan with the mushroom mixture. Add an additional 1/4 cup broth if the pan seems dry. Cook and stir until vegetables are tender and sauce is beginning to thicken, about 10 minutes.
Stir zucchini noodles into the pan with the sauce and cook to desired firmness, 3 to 5 minutes more.
Don't have a spiralizer on hand? Using a vegetable peeler: Apply light pressure with a vegetable peeler along the sides of the zucchini for wide, fettuccine-like slices. Or use a grater: Roughly shred the vegetable lengthwise against a box grater. Press away excess liquid. Noodles will be shorter.
Try mushroom broth, if you prefer.
Per Serving: 442 calories;9.9 g fat;
53 g carbohydrates;
43.1 g protein;
0 mg cholesterol;
1189 mg sodium.