If you need to make roasted beet puree, wrap three washed, trimmed, and dried beets in foil and roast in a 400-degree oven for 40 minutes or so, until they're pierced easily with a knife. Cool, peel, and puree in a blender or food processor until smooth. Preheat oven to 350 degrees. Prepare a 9x5 loaf pan by buttering generously. In a large bowl, whisk together the all purpose flour, whole wheat flour, baking powder, and salt. In a medium bowl, whisk together the beet puree with eggs, milk, and melted butter. Stir this mixture into the flour mixture with a wooden spoon just until incorporated. To make the cream cheese swirl, combine cheese, egg, four, dill, and salt in a small bowl and stir until smooth. Spoon about 2/3s of the beet batter into the prepared pan and spread to the edges to even out. Dollop cream cheese mixture over it, then top with the rest of the beet mixture. Run a butter knife in a swirling motion through the layers to create the swirl pattern. Smooth out the top somewhat, then bake for 45-50 minutes, until a toothpick inserted in the middle comes out clean (a few moist crumbs are okay). Cool on a wire rack for 10 minutes or so before removing from pan. Serve warm or at room temperature.