Banana Walnut Bread Pudding

Name: Banana Walnut Bread Pudding
Ingredients: Nonstick cooking spray, for greasing the baking dish; 1 medium loaf challah bread (preferably stale), cut or torn into 1-inch pieces (about 10 cups); 1 cup Diamond of California(R) Shelled Walnuts, roughly chopped; 2 cups heavy cream; 7 large egg yolks; 3/4 cup light brown sugar; 1 teaspoon ground cinnamon; 1 teaspoon kosher salt; 1 teaspoon vanilla extract; 1/2 teaspoon grated nutmeg; 3 ripe medium bananas, mashed; Vanilla ice cream, for serving