Place cashews in a small bowl, cover with hot water and set aside.
Cook pasta according to package directions. Just before pasta is done the cooking, add the sun-dried tomatoes to plump for 1 minute. Drain set aside.
While pasta is cooking, heat 1 tablespoon olive oil in a medium pan over medium heat. Add the onion and garlic, stirring occasionally until softened, about 5 minutes. Remove from heat.
Drain the cashews. In a blender or food processor, combine the onion, garlic, cashews, 2 cups of water, lemon juice, and 2 teaspoons of salt. Blend on high until well blended. Set aside.
Heat 1 tablespoon olive oil over medium-high heat. Add mushrooms, season with salt and pepper to taste and cook until softened and slightly browned about 5 minutes.
Add cream sauce to mushrooms, bring to boil, reduce temperature and continue to cook at low boil for 2-3 minutes, stirring occasionally.
Optional. Add the pasta to pan and toss to coat. Garnish with parsley and vegan parmesan cheese.