Preheat the oven to 350 degrees F. Spray two 9 inch loaf pans with cooking spray and then dust each with flour. Tap out any extra flour. You can also line the bottoms of the pans with parchment paper to make them easier to remove later.

In a large bowl, using a stand mixer or an electric mixer, cream together the butter and sugar until it is light and fluffy (about 5 minutes).

Continuing to mix, beat in the eggs one at a time and add the orange zest.

In a separate large bowl, sift together the flour, baking powder, baking soda and salt and set to the side.

In a small bowl, mix the orange juice, buttermilk and vanilla.

Alternating between the flour mixture and the buttermilk mixture, start to add them slowly to the batter. Continue to mix until all ingredients are well combined.

Divide the batter between the 2 loaf pans and bake for 40 to 50 minutes or until a toothpick inserted into the middle comes out clean.

Let cakes cool in the pan for about 10 minutes.

While the cakes are cooling, go ahead and make the orange syrup. Place a wire rack on top of a baking sheet and set to the side.

In a small saucepan, over medium heat, stir the orange juice and sugar together until the sugar is completely dissolved. Once sugar is dissolved, cook for about 3 minutes then remove from the heat.

Transfer the cakes to the wire rack and use a toothpick to poke holes in the tops and sides of the cakes.

Brush the orange syrup over the holes, allow it to soak in and repeat. Let the cakes cool completely while you make the glaze.

For the orange glaze, whisk together the powdered sugar and four tablespoons of the orange juice in a small bowl. Mixture needs to be thick, but you should still be able to pour it out. Add more orange juice, one tablespoon at a time, if needed to thin glaze out some.

Pour the orange glaze over the 2 cakes and allow to harden before serving (about 15 minutes).