1. Place dried mushrooms in a medium bowl and cover with 1 cup boiling water. Let stand 15 minutes. Drain mushrooms through a paper towel-lined sieve, reserving soaking liquid. Rinse mushrooms to remove any leftover grit and chop into small pieces; set mushrooms and soaking liquid aside.
2. Meanwhile, cook pasta according to package directions without added fat or salt. Transfer to a large bowl and cover with foil to keep warm.
3. Heat oil in a large saucepan over medium heat. Add garlic and fresh and dried mushrooms and cook until fresh mushrooms wilt and release juice, 3 to 5 minutes.
4. Dissolve cornstarch in 1/4 cup cold water and add to skillet with the reserved mushroom soaking liquid. Simmer 1 minute, until sauce thickens. Season to taste with salt and pepper.
5. Pour hot mushroom sauce over pasta, add spinach and toss to combine (hot sauce will wilt spinach leaves). Add parmesan and almonds and mix will.