Heat your oven to 350°F (175°C)
Lightly grease and flour your Bundt cake pan
Combine all the ingredients for the streusel topping with your hand and keep it aside
Combine the dry ingredients in a large mixing bowl, and stir with a fork to mix everything well.
Peel and core pears, then grate them. You’ll want two grated cups total; set them briefly aside.
In a medium bowl, combine the oil, eggs, sugar, grated pear, nuts (if using), and vanilla, and stir to mix everything well.
Add the pear mixture into the flour mixture and stir just until the flour disappears and the batter is evenly moistened.
Pour the batter into the prepared pan. Top with the cinnamon streusel topping.
Bake at 350°F (175°C) for 40/45 minutes, or until the bread is browned and firm on top and a wooden skewer inserted in the center comes out clean.