Preheat oven to 350°F. Line two 8" x 4" loaf pans with parchment paper, set aside.
In the bowl of a stand mixer, add in 2 cups persimmon pulp, 4 eggs, ⅔ cup bourbon, 1 cup butter, 1 teaspoon vanilla extract, and 2 cups granulated sugar. Mix on low until well-combined.
In a medium-sized mixing bowl, sift together ½ teaspoon ground nutmeg, ½ teaspoon ground cinnamon, 1 teaspoon salt, 2 teaspoons baking soda, 1 ½ cups all purpose flour, and 2 cups whole wheat flour. Add in the flour mixture to the persimmon mixture in three additions—letting mix completely before moving onto the next addition.
Fold in 2 cups chopped walnuts into the batter. Pour the batter evenly between the two loaf pans. Bake in preheated oven for 35-40 minutes, or until the bread is dark brown, and the top feels solid (not jiggly) when pressed on. Let cool completely before slicing.