Step 1: Prepare the Mushrooms

• Clean the Mushrooms: Gently wipe the mushrooms clean with a damp paper towel or mushroom brush to remove any dirt. Avoid soaking them in water as they can absorb too much moisture.
• Chop the Mushrooms: Finely chop the mushrooms. You can use a food processor for this step, pulsing until they are finely minced, but be careful not to over-process them into a paste. Alternatively, chop them finely by hand for more control over the texture.

Step 2: Sauté Aromatics and Mushrooms

• Sauté Onion and Garlic: Heat olive oil in a large skillet over medium heat. Add the finely chopped onion and sauté for 5-7 minutes, until softened and translucent. Add the minced garlic and sauté for another minute until fragrant, being careful not to burn the garlic.
• Sauté Mushrooms: Add the chopped mushrooms to the skillet with the onion and garlic. Increase the heat slightly to medium-high. Sauté the mushrooms for 10-15 minutes, stirring occasionally, until they release their moisture and then begin to brown and caramelize. This step is crucial to remove excess moisture and concentrate the mushroom flavor. Continue cooking until most of the liquid has evaporated and the mushrooms are nicely browned.
• Season and Cool: Season the mushroom mixture with salt, black pepper, dried oregano, and dried thyme. If using red pepper flakes, add them now. Stir well to combine the seasonings. Remove the skillet from the heat and let the mushroom mixture cool completely. Cooling is important so that the heat doesn’t cook the egg when it’s added later.

Step 3: Combine Ingredients and Form Meatballs

• Combine Ingredients: In a large mixing bowl, combine the cooled mushroom mixture, panko breadcrumbs (or breadcrumbs of choice), grated Parmesan cheese (if using), chopped fresh parsley, chopped fresh basil, and optional ingredients like sun-dried tomatoes and walnuts.
• Add Binder: In a separate small bowl, lightly beat the egg (or prepare flax egg). Add the egg (or flax egg) to the bowl with the mushroom mixture.
• Mix Gently: Gently mix all the ingredients together with your hands or a spatula until just combined. Be careful not to overmix, as this can make the meatballs tough. The mixture should be moist but hold together when gently pressed. If the mixture seems too wet, add a tablespoon or two more breadcrumbs. If it’s too dry, add a teaspoon of olive oil or water.
• Form Meatballs: Using your hands or a tablespoon or cookie scoop for uniform size, form the mixture into meatballs, about 1.5-2 inches in diameter. Gently roll them between your palms to smooth the surface. Place the formed meatballs on a baking sheet lined with parchment paper or lightly greased.

Step 4: Cook the Mushroom Meatballs

You can cook the mushroom meatballs in several ways: baking, pan-frying, or simmering in sauce. Baking is generally the healthiest and easiest method.

• Baking (Recommended Method): Preheat oven to 400°F (200°C). Drizzle the meatballs lightly with olive oil. Bake for 20-25 minutes, or until golden brown and firm to the touch. Flip them halfway through baking to ensure even browning.
• Pan-Frying: Heat a tablespoon of olive oil in a large skillet over medium heat. Add the meatballs to the skillet in batches, being careful not to overcrowd the pan. Cook for about 8-10 minutes, turning frequently, until browned on all sides and heated through. Pan-frying will result in a crispier exterior.
• Simmering in Sauce: You can also add the uncooked meatballs directly to your favorite simmering tomato sauce. Gently simmer in the sauce for about 20-25 minutes, or until cooked through and firm. This method will result in softer, more sauce-infused meatballs.

Step 5: Serve and Enjoy!

• Once cooked, remove the vegetarian mushroom meatballs from the oven, skillet, or sauce.
• Serve immediately while hot. They are delicious served in a variety of ways (see “How to Serve” section below).