Preheat oven to 350F. Grease a 9x5 loaf pan and set aside.
Peel pears. Chop the pears into 1/2 inch dice. Take 1/2 cup of the chopped pear and mash it well until it's basically pureed.
In a large bowl, mix together wheat flour, white flour, baking soda, baking powder, salt, and spices.
In a medium bowl, whisk together buttermilk, butter, eggs, maple syrup, and vanilla. Stir in chopped pears and pear puree. Pour the liquid ingredients into the dry ingredients and combine with a large spatula until just mixed together.
Add all streusel ingredients to a bowl and mix with your fingers until until well combined and there is no dry flour left.
Using the spatula, scrape the pear batter into the prepared loaf pan. Sprinkle the streusel over the top, patting it down to push it into the batter a little. This will help it adhere to the bread.
Bake the bread for 45 minutes. Reduce the temperature to 325F and bake for 15 minutes more. Allow the bread to cool for 1 hour on a rack. Then run a butter knife around the edges and carefully take the bread out of the loaf pan.