Preheat the oven to 350 degrees F. Grease a 9x5-inch loaf pan (I used baking spray with flour), and set aside.
In a medium-sized bowl, whisk together the flour, baking powder, baking soda and salt.
Grate the zest from two oranges and combine in a small bowl with the sugar. Use your fingers to press the zest into the sugar, removing any clumps, until fragrant and evenly distributed.
Supreme both oranges, one at a time, using a sharp knife (I use a chef’s knife, but some prefer a paring knife). Slice off the very top and bottom of the orange, creating flat ends. Place one end on a cutting board, then use your knife to remove the orange peel and white pith in sections, all the way around, maintaining the shape of the fruit.
Hold the fruit firmly in the palm of your hand or place it on its side on the cutting board (whichever feels more comfortable). To remove the segments, cut along the membrane toward the center, then slice along the adjacent membrane, until the slices meet and you can remove the segment. Repeat all the way around, placing the segments into a bowl.
Once the oranges are supremed, squeeze the membranes over a liquid measuring cup to extract the juice. Discard the membranes. Juice a third orange into the measuring cup, so you have approximately 1/4 cup juice. Add buttermilk until you have 2/3 cup liquid total. Pour into a large bowl along with the sugar and eggs, whisking until smooth. Whisk in the dry ingredients, then switch to a spatula and slowly fold in the olive oil, followed by the orange segments.
Pour the batter into the prepared loaf pan, smoothing out the top. Bake for 55 minutes, or until golden on top, with a toothpick coming out clean from the center. Allow to cool for 5 minutes, then remove from the pan and cool to room temperature.
Supreme the remaining 3 oranges and combine with the honey. Serve slices of cake topped with whipped cream, blood orange supremes and a drizzle of the orange honey juice.