Preheat oven to 350°F (175°C). Grease and flour an 8-inch (20cm) springform pan or line with parchment paper.

Place the chopped whole orange (peel and all) into a food processor or blender and pulse until smooth.

In a large mixing bowl, beat the eggs and sugar together until pale and fluffy.

Add the oil and processed orange mixture to the bowl and mix until well combined.

In another bowl, sift together the flour, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients, folding gently until just combined.

Pour the batter into the prepared pan and smooth the top.

Bake for 40–45 minutes or until a skewer inserted into the center comes out clean.

Allow to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.

Dust with powdered sugar before serving.