To make the pastry, combine the flour and 1 cup of the sugar in a large bowl. Make a well in the center and combine the melted lard or butter and 5 egg yolks in the well. Mix the ingredients into a dough with a wooden spoon. Add a little water if dough is too stiff. Knead the dough on a work surface for 1 minute. Set aside. In a small bowl, combine remaining sugar, the cinnamon, and the cocoa. Set aside.

Preheat the oven to 350 degrees.

Butter the bottom and sides of a 10-inch round baking pan.

Divide the dough in half. Roll each half of the dough out to a 12-inch circle. Fit 1 circle of dough into the bottom of the pan, letting it come up the sides about 2 inches. Let rest.

Beat the egg whites in a bowl until they just begin to stiffen. Add the sugar mixture a scoop at a time, and continue beating the whites until they are stiff. Fold in the candied citron and cheese.

Pour the filling into the pastry-lined pan and smooth the top evenly. Cover the mixture with the remaining circle of pastry. Crimp the edges of the dough together. Make a ¾-inch hole in the center of the top of the tart. Brush the top with the remaining egg yolk.

Bake the tart on a baking sheet on the center shelf of the oven for 1 hour or until golden brown.

Remove the tart from the oven and let cool on a rack for at least 30 minutes. Dust the tart with confectioners’ sugar just before serving.