Simmer the stock: In a large saucepan, heat 4 cups vegetable stock until gently simmering
Cook the onion and mushrooms: finely mince the onion and thinly slice the mushrooms. Set a pot on the stove with the stock to warm. Meanwhile, set a medium dutch oven with 3 tablespoons of olive oil over medium heat. Add 1 medium onion, finely chopped, and cook, stirring occasionally for 8 - 10 minutes, until they are soft and translucent. Reduce the heat as needed to minimize browning.
Saute the rest of the ingredients: Add 6 garlic cloves, minced, and cook on medium-low heat for 1 minute until aromatic. Add 1 15.5-ounce can white beans, rinsed and drained and stir to incorporate. Using the back of a wooden spoon, mash about half of the beans. Stir in 1 cup arborio rice, and cook for 1 minute to allow the grains to toast slightly. Season with a pinch of salt and black pepper.
Add 1/2 cup dry white wine, scraping up the bits from the bottom of the pan and bring to a simmer. Let the wine reduce for 2 - 3 minutes until it's at half the original volume
Cook the risotto: Add a ladleful of the warmed vegetable stock to the risotto and stir to incorporate. Simmer on medium-low heat until the liquid is almost fully absorbed, stirring occasionally. Season again with a generous pinch of salt and pepper.
Add another ladleful of stock, stir, and continue repeating the process of simmering the rice gently, stirring occasionally, and adding more liquid once the previous liquid is absorbed. You want the liquid to be almost fully absorbed without the rice sticking to the pan. Keep repeating the process until the rice is al dente. As the risotto cools, it will continue to thicken.
While the risotto cooks, make the herby breadcrumbs. Toast the breadcrumbs in a large pan tossing regularly until golden brown. Set aside in a bowl and mix in 2 cloves minced raw garlic and chopped parsley
To finish the risotto, stir in your desired amount of pecorino romano cheese while still in the dutch oven and serve.