Preheat the oven to 350°F.
In a large bowl, using an electric whisk, beat the sugar and butter until they are foamy.
Add the eggs one by one and mix after each addition.
Add the flour, cocoa, and baking powder; mix gently.
Add the diced pears. Mix.
Butter and flour a cake mold. Pour in the cake batter.
Bake for 35 minutes.
Poke the center with the tip of a knife. If the knife comes out clean, remove the cake.
Place the cake on a rack and let it cool for 5 minutes before unmolding. Serve warm or cold.