• Preheat the oven to 350 degrees
• Butter and flour a 9" cake pan. Set aside
• Sift the flour and baking powder in a bowl. Set aside
• Cut one orange into half. Chop one of them, (yes, with the rind) into smaller pieces then add to a blender and blend until almost pureed. 
• Squeeze juice from the other oranges and set aside
• In a mixing bowl, beat the butter and sugar using a hand mixer until fluffy. Add in the eggs and continue to mix until light and fluffy
• Add the orange juice, rind, sour cream, and the vanilla extract and mix
• Add the sifted flour to the butter-cream mixture and mix to combine
• Transfer the prepared cake pan and bake for 40-50 minutes or until a toothpick comes out clean when inserted
• Cool for 10 minutes. You can serve as is, dust with icing sugar or glaze as below

For the Glaze (optional)

• Combine the glaze ingredients in a pan and simmer for a few minutes (3-5 minutes) until it thickens into a syrup-ish consistency 
• Spoon and brush the mixture over the cake. Optional: Using a toothpick, poke all over the cake before brushing the syrup. This enhances the flavour and gives it a beautiful finish.