Preheat oven to 375°. Cook noodles according to package directions for al dente. Meanwhile, pulse one-third of the tofu in a food processor until pureed. Add tahini, olive oil and garlic; pulse until combined. Crumble remaining two-thirds of tofu into a large bowl. Add nutritional yeast, basil, lemon juice, salt, oregano and pepper. Continue to mash until texture resembles ricotta cheese. Stir tahini mixture into nutritional yeast mixture; stir to combine. Drain noodles.
Spread 1/2 cup pasta sauce into a greased 13x9-in. baking dish. Layer with 4 noodles, 1 cup sauce, half the sausage, and one-third of the tofu mixture. Top with 4 noodles, spinach, mushroom slices, one-third of the tofu mixture and 4 noodles. Top with 1 cup sauce, remaining sausage and remaining tofu mixture. Top with remaining noodles and sauce. Sprinkle with cheese.
Bake, covered, for 30 minutes. Uncover and bake until edges begin to bubble, 10-15 minutes longer. Let stand 10 minutes before serving.