Put on a pan of lightly salted water to boil the pasta in. Add the spaghetti once boiling, and cook on a rolling boil for 8-10 minutes, until al dente. Reserve the cooking water when draining.
In the meantime, heat up olive oil in a large frying pan.
Add the cubes of smoked tofu, season with salt and pepper and fry on medium-high heat, until golden brown.
Reduce heat to medium, add the herbs and garlic to the tofu and fry for 1 more minute.
Add the soy sauce, quickly stir in and proceed with making the sauce. If you are blending the silken tofu only now, add a splash of water to the frying pan to keep the soy sauce from catching.
Reduce heat, and stir in the blended silken tofu.
Add nutritional yeast, lemon juice and turmeric (if using).
At this point, the spaghetti should be just about done. Don't forget to reserve the cooking water when draining!
Stir ¼ cup of the reserved pasta cooking water into the sauce. (If you've already discarded it, just use hot water.) Don't worry if the sauce seems a bit liquid at this point.
Finally, add in the cooked spaghetti to the sauce and mix them in, until the sauce has thickened and the spaghetti are evenly coated with creamy sauce. Add a bit more starchy pasta water if it feels to dry or sticky at any point.
Serve topped with some freshly ground black pepper and a drizzle of olive oil.
Notes
Smoked tofu - If you can't find smoked tofu you can use extra firm tofu and add a splash of liquid smoke with the soy sauce. Alternatively you could use your favourite vegan bacon substitute, or fried mushrooms. Silken tofu - Can come in either soft or firm varieties. Either type will work for this recipe, just adjust the amount of pasta water you add to get the desired sauciness. Drain the excess water before you blend it. You can blend it in a food processor, or with an immersion blender.