In a small bowl, whisk the buttermilk, melted butter, vegetable oil, molasses, and egg. Pour the wet ingredients into the dry and stir just until combined (the batter will be a little bit lumpy). Pour the batter into the prepared pan and sprinkle with the blueberries. Sprinkle with the turbinado sugar. Bake for 40 to 45 minutes, until the cake is just beginning to pull away from the sides of the pan and a toothpick inserted in the center comes out clean. Cool the cake in the pan on a wire rack, then remove the sides of the pan, slice, and serve.