Preheat the oven to 350°F and line a 9 x 5-inch with parchment or grease. Set aside.
In a medium-sized bowl whisk together the flour, baking powder, baking soda, salt, and spices. Set aside.
In a large bowl or in a stand mixer with a paddle attachment, cream the butter and sugars. Beat until the mixture is pale in color and fluffy, about 2-3 minutes. Once the mixture is set, add in the eggs one at a time. Make sure the eggs are fully combined and beat in the vanilla.
On a low-speed alternate between adding the flour mixture and the sour cream. The mixture might look a little lumpy, but that is okay. Next, slowly add in the milk.
Once the batter is complete, fold in the pears. Do not over mix the batter.
Pour the batter into the loaf pan and sprinkle the top with cinnamon. Bake for about 50-55 minutes. The top should look golden brown when done and start to pull away from the sides of the pan. Let the cake completely cool before removing it from the pan.
The cake should last about 4-5 days in an air-tight container. It should be refrigerated due to the fruit.