In a skillet over medium heat, toast the walnuts for about 5-7 minutes until fragrant. Watch carefully to prevent burning.

Using a food processor, finely dice the mushrooms and onions until well combined but not pureed.

Heat a tablespoon of oil in the skillet over medium heat, then add the chopped onions and mushrooms, seasoning with salt and pepper. Sauté for about 6-8 minutes.

In the food processor, combine the oats, Panko breadcrumbs, walnuts, nutritional yeast, ground flax, and parsley or cilantro. Blend until mixed well.

Incorporate the drained and rinsed black beans, BBQ sauce, and tamari into the food processor. Pulse until well-combined but retains some texture.

Transfer the cooked onion-mushroom mix into the processor or a large bowl. Mix thoroughly and adjust seasoning.

Use a ½-cup measuring cup to portion out the mixture and form 8 patties. Arrange them on a parchment-lined baking sheet.

Preheat your oven to 375°F (190°C), then bake the patties for 15 minutes. Flip each one and bake for another 12-15 minutes.

Let your Mushroom Veggie Burgers cool for 5-10 minutes before serving.