Step 1: Preheat your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan, or spray with non-stick baking spray.
Step 2: In a medium bowl, combine the chopped pitted dates and boiling water. Let them soak for at least 10-15 minutes, or until softened. Drain well before adding to the batter.
Step 3: In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy, about 3-5 minutes with an electric mixer. Scrape down the sides of the bowl as needed.
Step 4: Beat in the eggs, one at a time, incorporating each egg fully before adding the next. Stir in the vanilla extract until just combined.
Step 5: In a separate bowl, whisk together the all-purpose flour, baking soda, ground cinnamon, nutmeg, and salt.
Step 6: Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix.
Step 7: Fold the drained dates and chopped walnuts into the batter using a spatula until evenly distributed.
Step 8: Pour the batter into your prepared baking pan and spread evenly.
Step 9: Bake for 30-35 minutes, or until a wooden skewer or toothpick inserted into the center of the cake comes out clean.
Step 10: Let the cake cool in the pan on a wire rack for about 10-15 minutes before inverting it onto the rack to cool completely.
Step 11: (Optional Glaze) Whisk together 1 cup powdered sugar, 2-3 tablespoons milk, and 1/2 teaspoon vanilla extract until smooth. Drizzle over the cooled cake before serving.