Heat 2 tablespoons of olive oil In a large sauté pan over medium high heat. Add the eggplant and cook until it turns a beautiful golden brown. Remove to drain on paper towels.
Add the remaining oil and mushrooms to the pan and sauté until they begin to turn golden brown. Season with salt and coarsely ground black pepper. Remove the mixture from the heat.
In a shallow gratin dish, mix the cannelini beans, eggplant, mushrooms, garlic, rosemary, and thyme. Arrange the tomatoes on top and pour the wine over all. Bake for about 30 minutes. Remove from the oven and stir.
Mix the breadcrumbs together with the melted butter, then sprinkle them on top of the cassoulet. Return to the oven and continue cooking for about 30 minutes, or until bubby, golden brown, and crisp.