Pre-heat the oven to 325 degrees. Grease a 9 x 5 inch loaf pan. Line the pan with parchment paper, leaving extra paper overhanging on the sides. Use a microplane to zest all 3 oranges and place the zest in a large bowl with the sugar. Use your fingers to coat the sugar with the zest. Juice all three oranges into a measuring cup. It should yield about 1/2 cup or so, depending on the size of the oranges. Pour enough buttermilk into the measuring cup with the fresh juice, to reach 2/3 cup total liquid. Pour the liquid over the sugar mixture and whisk together well. Add the eggs and continue to whisk until combined.

In another bowl, whisk together the flour, baking powder, baking soda and salt. Gradually whisk the dry ingredients into the wet ingredients. Using a spatula, gently fold in the olive oil. Pour the batter into the prepared pan. Please note that it is a wet batter. Bake the cake for about 45-50 minutes or until the top is golden brown, and a wooden skewer or knife comes out clean when inserted into the center of the cake.

While the cake is baking, combine the heavy cream, confectioners’ sugar and vanilla extract into a medium-sized bowl. Whip the cream to soft peaks, using a whisk or an electric mixer with the whisk attachment.

Cool the cake in the pan for about 5 minutes. Using the parchment paper, gently pull the cake out of the pan and let it finish cooling on a cooling rack. Serve with the fresh whipped cream and orange slices.