Preheat the Oven: Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

Prepare the Bean Mixture: In a large bowl, mash the white beans with 4 tablespoons (60 ml) of olive oil and 2 tablespoons (30 ml) of lemon juice using a fork or potato masher. The consistency should be slightly chunky, not completely smooth, but cohesive enough to hold together.

Cook the Aromatics: Heat the remaining olive oil (approximately 2 tablespoons or 30 ml) in a skillet over medium heat. Add the chopped shallots, ½ teaspoon kosher salt, and the crushed red pepper flakes. Cook for 3-4 minutes until the shallots are softened. Stir in the minced garlic and cook for an additional minute until fragrant. Remove from heat.

Combine the Filling: Transfer the sautéed shallot mixture to the bowl with the mashed beans. Once slightly cooled, stir in the shredded mozzarella, grated Parmesan, chopped oregano, panko breadcrumbs, and ¼ teaspoon ground black pepper. Mix until well combined.

Prepare the Mushrooms: Clean the mushrooms by wiping them with a damp cloth and remove the stems. Use a small knife to carefully cut out a bit of the mushroom center, creating a cavity for the filling. Place the mushrooms, cavity side up, on the prepared baking sheet. Drizzle the mushrooms with 1 tablespoon (15 ml) of olive oil and sprinkle them with ½ teaspoon kosher salt.

Stuff and Bake: Spoon the prepared filling into the mushroom cavities, packing it slightly to ensure it stays in place. Drizzle the filled mushrooms with the remaining olive oil (about 1 tablespoon or 15 ml). Bake in the preheated oven for 18-22 minutes, or until the mushrooms are tender and the filling is golden brown.