In a mixing bowl, cream the butter and sugar together, until light and fluffy for about 2 minutes on high. Add all the eggs at once, it will curdle that's normal. Add the lemon zest. Then, fold the flour, baking powder, and salt. IMPORTANT: Do not over mix.
Pour the preparation into your Flexipan®. Dust with sugar.
BAKE!
Bake for 45 minutes at 350F/180C. (Every oven heats differently, monitor your cake from 35min). It is ready when the toothpick inserted comes out clean.
Once your cake is out of the oven, let it cool down for about 10min. Then, Unmold, Serve and Enjoy with your Favorite tea or with a glass of Madeira! Bon Appétit!