Add the olive oil to a large saucepan and set heat to low-medium.

Add the chopped mushrooms, salt, pepper, oregano, and thyme, and sauté until the mushrooms are slightly caramelized and any water that the mushrooms have released has evaporated from the pan (approximately 10 minutes).

Add the black beans and sauté for an additional 5 minutes.

Add the mushroom and bean mixture to a food processor along with the walnuts, garlic cloves, and oat flour, then process until the ingredients are well combined but some texture remains (don’t try to achieve a very smooth purée).

Preheat the oven to 400 degrees Fahrenheit.

While the oven is heating, form meatballs by scooping out the meatball mixture into your hands (use 1 tablespoon of the mixture per meatball) then roll them into ball shapes before placing on a parchment paper lined baking sheet.

Bake the meatballs for 20 minutes, then flip them to ensure even cooking before baking for an additional 12 minutes.