Heat up the pan, and add vegan butter if desired.
In the meantime, cook noodles.
Add plant milk and flour to the pan, and stir until well blended.
Once the flavors are mixed, start the pesto. Place all ingredients in the blender except for the walnuts and blend until smooth.
Lightly blend the walnuts in, keeping the pesto chunky.
Mix the pesto into the alfredo, and add the noodles, and coat them thoroughly.