To a mixing bowl, sift together and combine the following: whole wheat flour, all-purpose flour, baking powder, salt, cinnamon, ginger, cloves, and nutmeg.
To a second large mixing bowl whisk and combine the following: pumpkin, egg, granulated sugar, canola oil, milk, and 1 teaspoon vanilla extract.
Slowly blend the flour mixture into the pumpkin mixture, stirring just until the batter is well combined.
Coat an 8-inch X 4-inch baking pan with canola oil cooking spray. Pour the batter into the pan, spreading and smoothing the top with a table knife, ensuring the corners are filled in and the surface is perfectly smooth and even.
Bake for 35-40 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow the cake to cool.
Meanwhile, prepare the Chocolate Glaze. To a mixing bowl, add the confectioners' sugar, cocoa powder, water, and 2 teaspoons vanilla extract. Stir until ingredients are well combined. If the glaze is too thick to spread over the cake, add ½ teaspoon of water at a time and stir until desired consistency is reached.
Run a table knife along every side of the cake, ensuring cake doesn't stick to the sides of the pan. Turn the pan over onto a tray or cutting board to remove the cake from the pan. Flip the cake so it's right-side-up. Use a small spatula to spread the chocolate glaze all over the top of the cake. Slice and serve.
To Store: cake should remain fresh for about 4 days if stored in an airtight container at room temperature in a cool, dark, dry location.