Cook the penne on medium heat according to the package instructions. Once the water has boiled, along with the pasta, add 1/4 tsp salt and the dried shiitake mushrooms. Let the mushrooms cook along with the pasta.
Meanwhile, on medium heat in a cooking pan (preferably non-stick), add the avocado oil, chopped garlic and onion. Sauté for 1-2 minutes until golden brown.
Add the sliced cremini mushrooms and thyme leaves to the pan. Sauté for around 8 minutes or until the water evaporates and the mushrooms are tender. Stir occasionally.
While the mushrooms are cooking, let the cashews soak in a cup of hot water for 5 minutes.
Once the pasta has cooked, start making the sauce. Add the soaked cashews, the shiitake (that was cooking with the pasta), the pepper, the nutritional yeast, the miso, 1/2 tsp of salt, the lemon juice and 1/2 cup of the water from the cooked pasta to a blender and blend into a creamy sauce.
Drain the pasta and add to the pan with the sautéed mushrooms. Add the arugula and the sauce as well. Mix well together.
Taste and adjust the salt and pepper to your liking.
Serve the pasta and decorate with cherry tomatoes cut in halves or quarters then dig in and enjoy!