Chop the mixed mushrooms into bite-sized pieces and dice the small onion. Mince the garlic cloves and set all aside.
Heat a large skillet over medium heat and add the olive oil. Once shimmering, add the diced onion and sauté for 3-4 minutes until translucent and fragrant.
Add the chopped mushrooms to the skillet. Cook, stirring occasionally, until they release their juices and turn deep brown, about 8-10 minutes. The mushrooms should look caramelized and crispy on the edges.
Push the mushroom mixture to one side of the pan. Add the minced garlic and cook for 30 seconds until fragrant, stirring quickly to avoid burning.
Pour in the vegetable broth and add the thyme and smoked paprika. Bring the mixture to a gentle simmer and cook for 5 minutes to allow flavors to meld and the sauce to reduce slightly.
While the sauce simmers, drain and rinse the soaked cashews. Transfer them to a blender with 1/2 cup water, a squeeze of lemon, and a pinch of salt. Blend until smooth and creamy, about 1-2 minutes.
Stir the cashew cream into the mushroom sauce. Lower the heat and cook for another 3-5 minutes, stirring constantly until the sauce thickens into a velvety coat that clings to the mushrooms.
Meanwhile, cook the pasta in boiling salted water until al dente, about 8 minutes. Reserve a cup of pasta water, then drain the pasta.
Add the cooked pasta to the skillet with the mushroom sauce. Toss well to coat, adding reserved pasta water if needed to loosen the sauce and help it cling to the noodles.
Serve the pasta hot, garnished with chopped parsley and a drizzle of olive oil for extra flavor. Enjoy the creamy, savory mushroom stroganoff immediately.
