In a bowl, rub the orange zest and the sugar with your fingertips, until the sugar is filled with the orange zest’s perfume. Add the soft butter to the bowl. In a stand mixer with the paddle attachment, beat the sugar and butter until pale and fluffy.

Add the eggs one at a time (they should be at room temperature) mixing well after each addition. Make sure to scrape down the sides of the bowl to combine everything together.

Sift the flour with the baking powder and add half of it to the batter.

Add the buttermilk and the orange juice to the mixture and combine.

Add the rest of the dry ingredients and mix until the batter is completely homogeneous. This should take just a couple of minutes.

Spray with oil or butter and flour a bundt cake mold. Pour the batter into the mold making sure there are no air bubbles in the batter.

Bake in a preheated oven at 180°C or 350°F for approximately 50 minutes, until a toothpick inserted comes out clean.

Wait 5 minutes and unmold. Let cool completely before frosting.

For the glaze, mix the sugar with the orange juice. You can add more juice or more sugar until you achieve the desired consistency. Cover the cake with the glaze and allow it to dry before cutting.