Heat the oven to 350°F (175°C). Lightly butter and flour a 10-inch tube pan or two 9-by-5-inch loaf pans.
In a large bowl, combine the flour, baking soda, baking powder, salt, and cinnamon.
Scoop out about 1/4 cup of the flour mixture, dump it in a small bowl, and toss in the chopped walnuts.
☞ TESTER TIP: Tossing the nuts in the flour mixture prevents them from sinking in the batter when folded into the cake in step 4.
In a medium bowl, combine the butter or oil, eggs, granulated sugar, grated pear, flour-coated walnuts, and vanilla, and stir to mix everything well. Scrape the pear mixture into the flour mixture and stir just until the flour disappears and the batter is evenly moistened.
Quickly and gently scrape the batter into the prepared pan(s) and bake at 350°F (175°C) for 60 to 70 minutes, or until the bread is handsomely browned and firm on top and a toothpick inserted in the center comes out clean.
Cool the pear bread in the pan(s) on a wire rack or on a folded kitchen towel for about 10 minutes. Then turn it out onto a plate or the wire rack to cool completely, top side up.
Serve as is, sprinkle with confectioners' sugar, or ice with the Buttermilk Glaze.
Make the buttermilk glaze (optional)
In a medium saucepan over medium heat, combine the buttermilk, sugar, butter, cornstarch, and baking soda. Bring to a gentle boil.
Immediately remove the pan from the heat, stir well, and cool to room temperature. Stir in the vanilla and then set the glaze aside to cool slightly.
Glaze the pear bread (optional)
Spoon the Buttermilk Glaze over the warm cake and let it cool completely prior to slicing.