Preheat your oven to 350°F / 175°C. Generously butter two medium-sized loaf pans (approximately 8x4 inches).
In a large bowl, sift or whisk together the whole wheat flour, baking powder, cinnamon, allspice, and salt.
Stir in the yellow cornmeal until everything is evenly distributed.
In a separate large bowl or the bowl of a stand mixer, cream the softened butter until smooth.
Add the brown sugar and beat on medium speed until the mixture is light and fluffy, about 2-3 minutes.
Beat in the eggs one at a time, followed by the lemon juice, mixing well after each addition until the batter is smooth. Scrape down the sides of the bowl, then thoroughly mix in the pumpkin purée.
With the mixer on low speed, alternately add the dry flour mixture and the milk to the wet , beginning and ending with the dry mixture.
Mix only until just combined—do not overmix.
Divide the batter evenly between the two prepared loaf pans, smoothing the tops with a spatula.
Bake for 1 hour and 20 minutes, or until a wooden skewer or knife inserted into the center of the loaves comes out clean. The top should be golden brown and firm to the touch.
Let the loaves cool in their pans on a wire rack for 5-10 minutes.
Then, carefully run a knife around the edges and invert the loaves onto the rack to cool completely before slicing.
