Turn the oven to 180 ° C and prepare the cake pan.
In a bowl, mix the flour, salt, baking powder and baking soda.Beat the eggs, orange peel and sugar with a mixer until they double in volume and the sugar has melted.
In a smaller bowl, mix the cocoa and coffee, then add hot water. Mix with a spoon until a homogeneous paste is obtained.
Over the egg mixture, add the yogurt and mix gently with a whisk or spatula. Then add the oil and the mixture of cocoa and coffee. Stir gently until smooth.
At the end, add the flour. The dough then goes in the tray and in the oven for about 35 minutes, or do the toothpick test. After baking, leave the cake in the pan for about 5 minutes, then remove and leave to cool on a grill.