Preheat the oven to 375 degrees. Lightly oil a 10-inch cake pan. Line the pan with parchment or waxed paper and lightly oil the paper.
In a medium bowl, combine the flour, sugar, cocoa, baking soda, baking powder, and salt.
In a large bowl, whisk together the eggs, coffee, buttermilk, oil, and vanilla extract. Gradually stir the flour mixture into the egg mixture. Mix until thoroughly blended.
Line the bottom of the cake pan with the pears in a circular design. Pour the batter on top of the pears. Bake for 55 minutes, or until a wooden pick inserted in the center comes out clean.
Place on a cooling rack and let stand for 10 minutes. With a butter knife, cut around the edge of the cake, loosening the sides. Invert the pan onto a plate. Using the handle of the knife, vigorously tap the top of the pan, even shaking it a bit, to loosen the cake. Leave the pan over the cake for 15 minutes. Remove the pan and let the cake cool completely.