Preheat the oven to 350°F. Line the bottom of a 9-inch cake pan with parchment paper and spray with non-stick spray. Set aside. In a mixing bowl, combine the rye and all-purpose flours, baking soda, salt, ground ginger, cinnamon, allspice, and cloves. Whisk to combine and then set aside.
Cut one pear in half and set aside one half to garnish the cake. Peel, core, and peel the remaining pears and then set aside. Use a rasp, or microplane, to finely grate the fresh ginger and then set aside.
In a separate bowl, combine the brown sugar, eggs, vegetable oil, buttermilk, and molasses. Whisk until combined. Add the grated pears and fresh ginger.
Add the dry ingredients to the wet ingredients and whisk just until combined. Pour into the prepared cake pan. Thinly slice the remaining pear and arrange decoratively on top of the batter.
Bake the cake for 45 to 50 minutes until a skewer inserted in the centre comes out clean and the top springs back when touched. Allow to cool for 5 minutes and then turn the cake out onto a rack to cool. Enjoy!
Notes
*Half of one pear is set aside for garnish, the remaining 1 1/2 pears should equal about 260 g once peeled and grated. If the pears are small, you may need to use some of the reserved pear to equal 260 g grated. **To substitute milk, add 1/2 tsp lemon juice or vinegar to an equal amount of milk and let sit 5 minutes to curdle. Proceed with the recipe.