Preheat the oven to 170 C/ 340 F and line a 20 cm cake tin with baking paper.
In a bowl, mix butter, sugar and eggs together until fully combined.
½ cup unsalted butter, 1 cup caster sugar, 3 large eggs
Stir in flour, baking soda and orange zest.
2 cups self-raising flour, 2 tbsp orange zest
Scoop the batter into the cake tin and bake for 45-55 minutes. Allow it to cool.
Make the orange glaze: In a small bowl, stir together the sugar and orange juice, then pour over the cake while warm and leave to cool in the tin for 2-3 hours and then cut and serve.
¼ cup orange juice, ½ cup caster sugar
Notes
Store it in a sealed container in the fridge for 3-4 days.