Start by ricing the cauliflower. Wash the cauliflower, removing any leaves. Cut into florets. Working in batches, put a handful of cauliflower into the bowl of a food processor. Pulse a few times until the cauliflower has the size and texture of ground meat. Pour into a bowl, set aside and repeat with the remaining florets. In the end you should have 4 cups of cauliflower.
In a large saucepan or dutch oven over medium heat, heat 1 tablespoon of olive oil. Add onion and carrot and season with a pinch of salt and few cracks of black pepper. Cook, stirring occasionally until carrot has softened, about 4 minutes. Add garlic and cook 1-2 minutes longer.
Add the 2 remaining tablespoons of olive oil and the 4 cups of the processed cauliflower. Cook stirring occasionally until cauliflower starts to soften, about 5-7 minutes.
Reduce heat to simmer and add crushed tomatoes, tomato paste, sun dried tomatoes, oregano, basil and crushed red pepper flake and more black pepper. Stir to combine.
Simmer sauce for about 25-30 minutes. It should be nice and thick.
Taste for seasoning and remove from heat and stir in the miso paste. Be sure to stir it in really well. No one wants a chunk of miso!
Serve over your favorite pasta.