Created by KittenCal on October 3, 2012
Step 1: Preheat oven to 400 degrees F. Place the mushroom caps onto a baking sheet stem-side down. Bake for about 6-8 minutes or long enough to release their moisture and dry out. Pat the mushroom caps dry using paper towels to remove any excess moisture.
Step 2: Turn the caps stem-side up then brush each cap with olive oil. Season each cap with coarse black pepper and a little salt. Reduce oven temperature to 350 degree F.
Step 3: In a bowl combine drained spinach with onion, garlic, chopped fresh parsley and chopped walnuts; mix to combine well. Season with salt and pepper.
Step 4: Divide the mixture between the caps. Lightly sprinkle crumbled feta cheese over the top of each cap (don't use too much cheese about 1 tablespoon per cap should be plenty). Bake (350 degree F) uncovered for about 15 minutes.