Preheat the oven to 160°C (350°F).
In a bowl, mix the flour, the baking powder, the first part of the sugar (80g), the lemon zest and the salt pinch.
In another bowl, mix the egg yolks, the olive oil, the milk and lemon juice.
Pour the dry ingredients (your flour mixture) over the liquid ingredients (your egg yolk mixture). Mix to obtain a homogeneous mixture, without insisting.
Place the egg whites in a bowl. Whisk them. When they start to get foamy, gradually add the rest of the sugar (30g). Continue to whisk until the whites are firm but supple (i.e. not too firm). Stop whisking as soon as you have the famous stiff peaks.
Softly add the whisked whites to the dough.
Pour the mixture into a ungreased mold (without paper around the edges), and bake for about 45 minutes (or until the dough is cooked).
Once the dough is cooked, let it cool down in its mold, upside down, on a grid. Then, gently remove it from the mold by running a spatula (or a knife) around the edges.