1. In a medium bowl, sift together cake flour, baking powder and salt. Set aside.
2. Microwave until the butter melts. Set aside.
3. In a large bowl, whisk eggs and add sugar at a time. Mix together well with an egg beater.
4. Add orange zest, orange juice and Cointreau. Mix them to combine evenly.
5. Add dry mixture into the egg mixture and mix together well.
6. Pour the melted butter into the mixture and mix with a rubber spatula until thoroughly combined.
Chill the Madeleine batter at least for about 2 hours in the refrigerator or even let it sit overnight before baking.
7. Preheat the oven to 190C degree.
8. Lightly coat madeleine pans with vegetable oil spray or butter and dust with flour, dab away excess oil. Spoon the batter into mold and bake the Madeleine for about 10 mins or until puffed and lightly brown.