1. Put a skillet on the stove over medium heat. White the pan heats, finely dice the mushrooms and onion. Add them to the pan with the olive oil, and cook for 10 minutes, stirring occasionally, until golden brown. Add garlic powder, oregano, rosemary, salt, and pepper, and turn off the heat.

2. While the mushroom mixture cools, preheat the oven to 400 degrees Fahrenheit and line a sheet pan with parchment paper or aluminum foil. Spray the pan with nonstick cooking spray, or drizzle lightly with olive oil.

3. Put all remaining ingredients into a mixing bowl, and mash together with a potato masher or fork. You want the beans to be mostly mashed, with some small chunks remaining. When mushrooms have cooled slightly, add them to the bean mixture, and stir well to combine.

4. Use a small ice cream scoop or a spoon to portion out 2 Tablespoon-sized balls. Roll between your fingers to get a more circular shape. Spread out the balls on the pan like cookies, and either spray them with more cooking spray, or drizzle them lightly with oil. Bake for 15 minutes, then flip and bake 10 more minutes. Serve warm with marinara sauce to dip, or put them on top of your favorite spaghetti. Leftovers keep well in the fridge for up to 5 days, though are best reheated in the oven as they start to fall apart slightly if reheated in sauce or in the microwave.