In a large bowl, whisk to combine oil, eggs, sugar, baking powder, baking soda, blood orange zest, and vinegar.
Working in 3 batches, alternate folding in the flour and the greek yogurt. Do not over mix.
Pour batter into prepared pan and bake for 45 minutes, until a knife inserted in the center of the loaf comes out clean. Allow to cool completely while making the glaze.
Juice the 4 blood oranges in a small saucepan. Heat over medium high heat to reduce the juice to about 2 tablespoons (the liquid should be about half it’s original volume).
Take the juice off the heat and mix in the powdered sugar, vanilla extract, and milk until well mixed and smooth. Add a little more milk if you need to thin it out.
Pour glaze over cooled cake. Garnish with blood oranges or edible flowers.