Preheat the oven to 400ºF.
Heat olive oil in a large frying pan over medium heat. Add shallots and sauté, stirring frequently, until soft and lightly caramelized, about 4 minutes. Stir in garlic and cook until fragrant, about 30 seconds.
Add spinach, salt, black pepper, and white wine. Cook, stirring frequently, until the spinach is wilted and dark green, 2 to 3 minutes.
Reduce the heat to medium-low and stir in heavy cream, Parmigiano Reggiano, and ½ cup of the cannellini beans. Using a fork or masher, mash the beans directly in the pan until the mixture is thick and creamy.
Stir in the remaining cannellini beans, butter beans, and Parmesan Stock. In a small bowl, whisk cornstarch with water until smooth, then stir the slurry into the pan. Transfer the pan to the oven. Bake for 15 minutes until thickened and bubbling.
Meanwhile, place the baguette directly on the wire rack in the oven and toast for 8 to 10 minutes, until the crust is crisp and the bread is warmed through.
Spoon the creamy beans into bowls. Garnish with crumbled Parmesan Crisps and serve with Lemon Salsa Verde on the side.
