Preparation time: 20 minutes
Baking time: 10 minutes

1. Preheat the oven to 210° C (425° F).
2. Butter the financier pans.
3. Wash and brush the orange, grate the zest finely and squeeze the juice.
4. Separate the egg yolks and whites.
5. In a bowl, whisk the egg yolks with the sugar until light and pale, then add the flour.
6. Melt the butter in a saucepan; add the orange zest and juice.
7. Incorporate into the batter.
8. Beat the egg whites to stiff peaks and gently fold them into the batter.
9. Half-fill the financier molds.
10. Bake for 10-12 minutes.
11. Remove from the oven, unmold onto a rack and let cool completely.