Begin by preheating your oven to 350 degrees F.
Line an 8 x 4 loaf pan with parchment paper and spray with baking spray. Set aside.
In a large bowl, whisk together the flour, baking powder, baking soda, and spices. Set aside.
In a medium bowl, whisk together the pumpkin puree, brown sugar, sour cream, eggs, canola oil, and vanilla extract. Add this mixture to your flour mixture and mix until just combined.
Next, mix up the cream cheese filling by whisking together the cream cheese, sugar, egg yolk, flour, and vanilla extract. Mix until smooth.
To your prepared loaf pan, add half of the pumpkin mixture. Create a small well in the batter and then add in the cream cheese mixture. Leave a 1/4-inch border around the edges of the pan. Top with the remaining batter, and smooth out the top.
Bake for about 60 - 65 minutes or until a toothpick inserted near the center comes out clean. Allow the loaf to cool in the pan for about 10 minutes. Then, use the parchment paper to remove the loaf from the pan, place it on a rack, and allow it to cool completely.
In the meantime, prepare the cinnamon glaze by whisking together the confectioners' sugar, cinnamon, and enough milk to achieve a thick drizzling consistency.
Once cooled, drizzle the glaze onto the bread. Slice and enjoy!