All you need is:
75g of butter
2 cups of all purpose flour
Half a cup of sugar
Tea spoon of baking powder.
4 – 5 red grapefruits
Mix eggs, melted butter and sugar, add slowly flour and knead everything till you get a smooth dough. Let it rest for half an hour in the fridge.
In the meantime peel the grapefruits and cut them into slices.
Roll the dough in a circle shape and place the grapefruits on it. Let outter 5cm of the dough free and after you place the grapefruits fold the dough over the fruits.
Bake it for 30min on 180°, or until you get a golden crust.