While the squash is roasting, do all your veggie prep and work on your sauce:
In a large pot over medium heat, heat olive oil. Add tempeh, soy sauce, maple syrup, and salt, and cook until browned, stirring frequently (about 5 minutes).
Add the onion, mushrooms, and garlic, and cook until sweated and starting to brown (about 10 minutes.) Deglaze the pan with 1-2 Tbsp water if the tempeh and veggies look like they might burn. Stir to scrape up the browned bits on the bottom.
Stir in tomato paste and salt and cook until the tomato paste is starting to brown (2-3 minutes.)
Squeeze the tomatoes into the can using clean hands to break up, then stir in the remaining juices from the can. Toss in the bay leaf and bring the sauce to a boil. Reduce to a simmer and cook until the tinny taste is gone from the tomatoes (at least 20 minutes, but for as long as 1 hour—-the longer you cook, the better it will taste.)
Serve over spaghetti squash or with pasta of choice and enjoy.