Preheat oven to 375 degrees Fahrenheit. Grease and flour one 9x5-inch loaf pan.
In a large bowl, whisk to combine the egg, pumpkin, brown sugar, granulated sugar, oil, sour cream, vanilla, cinnamon, pumpkin pie spice, and nutmeg.
In a separate bowl, combine the flour, baking powder, baking soda, and salt. Fold dry ingredients into wet ingredients until just combined; don't over-mix; set aside.
In a large bowl, beat the egg, cream cheese, granulated sugar, and flour with a hand mixer until smooth.
Pour ⅔ of the pumpkin batter into the prepared bread pan, smoothing the top and spreading to the corners.
Drizzle the cream cheese batter on top, completely covering the pumpkin layer underneath.
Gently dollop spoonfuls of the remaining pumpkin batter over the cream cheese layer and gently smooth over with a spoon.
Bake for 48 minutes or until the top is domed, golden and the center is set (bread will spring back when touched). *TIP: Cover bread with a sheet of foil the last 15 minutes to prevent too much browning.
Allow bread to cool in the pan for about 15 minutes before turning it out onto a wire rack to cool completely before slicing and serving. Store in an airtight container up to 1 week.