Step 1

Bring 1 cup of water to a boil. Combine dried mushrooms and rosemary in a small bowl, and add the boiling water. Set aside to steep for 20 minutes.

Step 2

Preheat a large saute pan over medium/low heat (optional -- if making the baked version, choose an oven-proof skillet large enough to hold the finished pasta (3 liter/quart); use it during both the sauteing and baking.) Add butter and garlic to the pan and sauté for about 1 minute. Increase heat to medium, and add the sliced mushrooms. Stirring occasionally, saute until the mushrooms are tender, about 15 minutes. Add the tamari, and cook for another minute or so. Remove from heat, and measure out a heaping 1/2 cup of the mushroom/garlic mixture.

Step 3

Heat a large pot of water for the pasta. Salt it generously, and cook pasta until not quite al dente. The pasta will finish cooking in the sauce. Drain in a colander.

Step 4

In a high-speed blender combine the steeped mushroom-rosemary mixture (including the liquid), 1/2 cup cooked mushroom mixture, cashews, 1 package cheese, miso, tapioca, nutritional yeast, salt, onion powder, and nutmeg. Blend until completely smooth.

Step 5

Pour the sauce into the saute pan with the mushrooms (if pan isn't large enough to hold the finished recipe, use the pasta pot). Bring to a simmer, and add the cooked pasta to the sauce. Stir to coat. Add the spinach, and cook for a few more minutes or until spinach is wilted and dark green. Taste and add salt and pepper, if desired. For stovetop version, set aside to rest and thicken for 10 to 15 minutes before serving.

Step 6

Preheat oven to 375 degrees F (190 C). Combine breadcrumbs, olive oil, and salt in a small bowl.

Step 7

Fold about half of the shredded cheese into the pasta. If you need to transfer the pasta to a baking dish, do that now. Sprinkle the remaining cheese on top, followed by the breadcrumb mixture.

Step 8

Bake for 15 minutes or until breadcrumbs are lightly brown and crisp. Broil for 2 to 3 minutes, if needed. Let rest 10 minutes, and serve.