Cook the pasta in a large pot of well-salted boiling water according to package directions until al dente. Drain and set aside, reserving ¼ cup of the pasta cooking water.

While the pasta cooks, combine the silken tofu and lemon juice in a blender or food processor. Blend until completely smooth and creamy, about 1 minute. Season with salt and pepper. Set aside.

Heat the olive oil in a large, wide skillet over medium heat. Add the garlic and sauté for 1 to 2 minutes until fragrant and lightly golden — do not let it brown. Add the asparagus, peas, squash, sun-dried tomatoes, and ¼ cup water. Cover and cook for 4 to 5 minutes, stirring once halfway through, until the vegetables are just tender-crisp.

Pour the silken tofu sauce over the vegetables and stir to coat. Cook over low heat for 1 to 2 minutes until heated through. If the sauce seems thick, stir in a splash of the reserved pasta water to loosen it.

Add the drained pasta to the skillet and toss well to combine everything. Stir in the fresh parsley or basil. Taste and adjust salt and pepper. Serve immediately.