Boil water for the pasta in a pot. In a pan, saute onion and garlic in avocado oil on medium heat for 1-2 minutes. Toss in the mushrooms and saute for 7-10 minutes until cooked through.
Toss the pasta into the boiling water and cook according to the package's instructions. Add coconut milk, vegetable stock, spices and oat flour into the pan.
Use a whisk and ensure the oat flour has been well combined and there are no lumps. Cook the sauce for 5-7 minutes on medium heat, whisking occasionally, until the sauce has become creamy.
Once the pasta is cooked through, drain the pasta and add it into the pan with the sauce. Coat the pasta in the sauce and serve with shredded vegan parmesan, if desired.