Preheat the oven to 175°C (350°C) and grease an 8 inch round bundt cake pan.
Combine the flour and baking powder into a bowl and whisk together. Set aside.
In another bowl, add the butter and sugar and beat using a handmixer until smooth, fluffy and creamy for about 3 minutes. If your using a stand mixer, use the paddle attachment and follow the same steps.
Add 1/2 cup of the orange curd and continue to beat until well combined about 45 seconds, then one at a time add the whole eggs followed by the egg yolks beating inbetween each addition for about 60 seconds.
Combine the flour with the mixture and mix until the batter is smooth about 2-3 minutes.
Deposit the batter into the cake pan.
Place into preheated oven and bake for 45-50 minutes or until the internal temperature of the reached above 96°C (205°F) Alternatively you can insert a toothpick into the center, the cake is baked if the toothpick is comes out clean.
Remove the cake from the oven and allow to cool in the pan for 10 minutes, before removing it onto a slight deep serving plate.
In the meantime, prepare the orange glaze sauce: Add the sugar, orange juice and butter into a small pot and cook on medium heat until the sugar has dissolved stirring constantly, about 6-8 minutes.
Remove the glaze from the heat and pour over the warm orange cake.
Serve slices of orange cake with a spread of the remaing curd.