If baking, preheat oven to 350°F (177°C). Line a baking tray with parchment paper.

Peel and finely chop the small onion. Peel and mince the 3 garlic cloves.

If you do not have walnut meal, pulse 1 cup walnut halves in a food processor until they form a coarse meal; measure out 1/4 cup walnut meal for the recipe.

Cook 1/2 cup rice according to package instructions (or use 1/2 cup leftover cooked rice); drain any excess liquid and set aside.

Gently clean the 11 oz button mushrooms with a paper towel or clean cloth and slice them.

Heat 1 Tbsp olive oil in a large skillet over medium heat. Add the chopped onion and minced garlic and cook until soft and translucent.

Add the sliced mushrooms to the skillet. Season with salt and pepper to taste, 1 tsp dried basil, 1 tsp dried oregano, and 1/2 tsp ground cumin seeds. Stir and cook until the mushrooms are soft and have released and reduced their moisture.

Transfer the sautéed mushroom mixture to the bowl of a food processor. Add 1/4 cup walnut meal (or the pulsed walnut meal), 1 Tbsp nutritional yeast, 1/2 tsp sweet smoked paprika, 1 + 1/2 tsp soy sauce or tamari, and the 1/2 cup cooked rice.

Add 2 Tbsp corn starch to the food processor. Pulse the mixture gently in short bursts; do not purée. Stop when the mixture holds together but still has visible chunks and texture. Work in batches if your processor is small.

Transfer the processed mixture to a large bowl. Test whether you can form a ball: the mixture should be soft and may stick to your hands a bit. If it is too sticky, add additional corn starch as needed and mix until you can form balls that hold their shape.

Use about 2 tablespoons of the mixture for each meatball and shape with your hands. Place formed meatballs on the prepared baking tray, leaving a little space between them.

To bake: bake at 350°F (177°C) for 20–30 minutes, turning the meatballs halfway through baking, until a crispy crust forms.

To pan-fry instead: heat a thin layer of the listed olive oil in a frying pan or large skillet over medium heat. Fry the meatballs 2–3 minutes per side (adjust time as needed) until browned on all sides and heated through.

Serve the meatballs with one of the listed sauces: Healthy Vegan Marinara Sauce, Caramelized Carrot Sauce, Vegan Mac and Cheese Sauce, or Vegan Cashew Alfredo Sauce.