Soak the sunflower seeds in hot water for about 20 minutes.
Prepare the vegetable stock, and prepare the pasta according to package directions.
Heat the olive oil in a pan over medium heat, and add the carrot and onion.
Cook, stirring, until soft, then add the garlic and cook until fragrant.
Drain the soaked sunflower seeds, and add them to a blender along with the carrot mix, vegetable stock, cornstarch, nutritional yeast, tomato paste, lemon juice, paprika, chilli flakes, miso, mustard and turmeric.
Blend until very smooth.
Once the pasta is ready, drain the cooking water, and pour the sauce into the pasta.
Mix it in, and serve.