In a large wok or saucepan over medium-high heat, warm 2 tablespoons of the oil, and sauté the onions and garlic with a pinch of salt for about 5 minutes until soft and translucent.
Transfer half of the onion and garlic mixture to the blender, and add 1 teaspoon of the salt, vegetable broth, canned tomatoes, sun-dried tomatoes, basil, thyme, oregano, sweetener, and red pepper flakes and blast on high for 30 to 60 seconds until the sun-dried tomatoes are pulverized.
Throw the cauliflower into a food processor fitted with the S blade, and pulse until you have very tiny pieces just larger than rice (the size of ground beef). You may have to do this in batches.
Turn on the pot with the remaining half of the onion and garlic mixture to medium heat. Add the ground cauliflower to the pot, and sauté for about 10 minutes until just cooked through. Add the mushrooms, and the remaining tablespoon of oil, and sauté for about 2 minutes until just softened.
In a small bowl, mix the tomato paste, balsamic vinegar, and mustard together until well combined and add this mixture to the cauliflower mushroom mixture until well combined and evenly coated.
Add the blended tomato mixture and the remaining teaspoon of salt and simmer, uncovered, stirring every few minutes for 15 to 20 minutes, until the sauce has thickened and slightly reduced, and the flavors have meshed.
You should have about 6 cups (1.4kg) of bolognese. Place 1 cup (240g) of bolognese into six sealable freezer containers or zip-lock bags, and place in the freezer for future meals. (Or place one or two in the fridge for the meal plan.)