1. Using a wet paper towel, wipe all mushrooms to remove any soil.

2.Pop out mushroom stems. Place mushroom caps in a sealable plastic bag and add salad dressing, making sure all the mushrooms are coated with dressing. Marinate the mushrooms for 30 minutes. Remove mushrooms from dressing and set aside.

3. In a medium bowl, combine lemon juice, garlic salt, onion and avocados. Coarsely mash, combining all ingredients. Spoon avocado mixture into a sealable plastic bag and seal tightly.

4. Push mixture away from one of the bottom corners of the bag. Using scissors cut a small hole in this corner of the plastic bag. Squeeze a generous amount of the avocado mixture through the hole in the bag into each mushroom cap and sprinkle with feta cheese. Serve.

*Large avocados are recommended for this recipe. A large avocado averages about 8 ounces. If using smaller or larger size avocados adjust the quantity accordingly.