• If the mushrooms are large, break them into 3-4 pieces each with your fingers and add half of them to the food processor. Pulse the food processor to finely mince the mushrooms. Note that you don't want to process them so much that they turn into a paste. Transfer the minced mushrooms to bowl and repeat with the remaining mushrooms
• Add 1 Tablespoon olive oil to a large skillet over medium-high heat. Add the chopped mushrooms and 1/2 teaspoon of the kosher salt. Cook the mushrooms until all of the moisture has been cooked out, and the mushrooms begin to clump together and resemble cooked ground beef (about 10 minutes). Remove from heat and allow to cool.
  
• While the mushrooms are cooling, you can start mixing up the remaining meatball ingredients. In a large bowl add 1 pound lean or extra lean ground beef, 1/2 pound ground turkey, chicken, or pork or Italian Sausage, 1 cup panko, 2 large eggs, 2 Tablespoons grated Parmesan cheese, 2 cloves garlic, 1 teaspoon dried basil, 1/2 teaspoon dried oregano, 1/2 teaspoon onion powder, 1/2 teaspoon freshly ground black pepper, and the remaining 1/2 teaspoon of kosher salt. Add the cooked mushrooms once they are cool enough to handle with your bare hands.
• Mix all of the ingredients together with your hands or a large spoon until everything is evenly distributed. Using your hands, form the mixture into 1-1 1/2" meatballs (you should end up with somewhere around 30 of them). Place the meatballs on a foil-lined baking sheet. If you're not going to cook the meatballs right away, cover the sheet with plastic and refrigerate until you're ready.
  

To bake:

• Remove the plastic from the baking sheet and bake at 350°F for 20 minutes.

To pan-fry:

• Add 1 Tablespoon of olive oil to a large skillet. Cook the meatballs over medium to medium-high heat, ensuring that you turn the meatballs regularly to brown on all sides. Note that you will likely have to do this in more than one batch.

To Air-Fry

• Add the meatballs to your air-fryer and cook the meatballs at 350°F for 8 minutes, turn the meatballs, and cook for an additional 2-3 minutes. You will probably have to cook the meatballs in multiple batches.