Preheat oven to 350°F (175°C)
Prepare your ingredients by gathering all your ingredients on the counter. Ensure that your butter is softened and your eggs are at room temperature for optimal mixing.
In a blender or food processor, combine the pieces of orange (with rind) and blend until smooth.
In a large bowl, whisk together the blended orange mix with sugar, eggs, yogurt, and butter until well combined.
In another bowl, sift together flour and baking powder to ensure there are no lumps. Gradually add this dry mixture to the wet ingredients while stirring gently to combine.
Pour the batter into a greased cake pan and sprinkle with sugar on top. Place it in the preheated oven and bake for about 55 minutes or until golden brown.
Once baked, allow the cake to cool in the pan for about ten minutes before transferring it onto a wire rack to cool completely. Slice and serve as desired.