Heat a large heavy-based saucepan on medium-high heat. Once hot add the olive oil, and then the shallots and season well.
Stir frequently and cook the shallots until the pan starts to brown, about 5 mins. Add a few spoons of water and continue cooking, adding more water every few minutes and stirring frequently to prevent burning. Keep doing this until the shallots are deep golden brown – about 15 minutes.
Reduce the heat and add the garlic slices. Cook for another 5-10 minutes then add the chilli flakes and oregano. Stir to coat the shallots and garlic.
Now add the tomato puree, tamari, nutritional yeast, and sundried tomatoes and stir to combine. Turn the heat to low. Let the sauce reduce until it is a deep brown.
Cook the pasta according to package instructions reserving about 1 cup of the cooking water, then drain the pasta.
Add a few spoons of the pasta water to the sauce and stir. Add the cooked pasta and more water if needed until all of the pasta is coated.