Preheat the oven to 350°F. Butter and flour a 10-inch springform pan. Set aside. In a medium bowl, sift together the dry ingredients: flour, baking powder, and salt. In another small bowl, whisk together the buttermilk, melted butter and olive oil.
In a stand mixer (or large bowl with a hand mixer) beat the eggs and 1 cup sugar until pale and fluffy, about 5 minutes. Alternately add and mix the dry and wet ingredients in three batches. Pour the batter into the prepared pan. Top with the chunks of stone fruit and sprinkle with the remaining 2 Tbsp of sugar.
Bake in the oven for 35-40 minutes or until the sides pull away from the cake pan. Transfer to a wire rack and let cool to room temperature.