Preheat an oven to 400 degrees F.
Butter an 8-inch cake pan and dust with sugar and flour.
Beat the eggs with the sugar to pale yellow ribbons.
Beat in the milk, oil and orange zest.
In a small bowl, sift the flour with the baking powder, baking soda and salt.
Add the flour mixture to the egg mixture a tbsp at a time and stirring well after each addition.
Pour batter into prepared cake pan and bake for 1 hour.
Remove cake from oven.
Let cool slightly on a rack, invert and cool completely.
For making the syrup:-
10)Using a sharp paring knife to cut the orange, rind off the orange used for zest and the remaining orange, leaving the bitter white pith on the orange.
Cut the skin into very thin strips and reserve.
Cut away and discard the white pith, remove the orange supremes, and reserve.
In a large sauce pan, combine the orange juice, sugar and thin orange strips.
Bring to a simmer and cook for 30 mins or until a thick syrup.
Strain the syrup and reserve the orange strips, along with 1/2 cup of the syrup.
Use a toothpick to poke holes in the top of the cake.
Pour the warm strained syrup all over the cake so that it soaks through.
Place the remaining 1/2 cup syrup in a small sauce pan.
Bring to a simmer and reduce to a few tbsp.
Use a spatula to spread the thick glaze over the top of the cake.
Place the cake on a serving platter.
Arrange the reserved orange strips and orange supremes on top of the cake.