In a small bowl dissolve the yeast in 60ml warm water, add a pinch of sugar and wait until foamy, about 5 minutes.
In a large bowl, combine flour and salt and make a well in the center.
Add the remaining water, the yeast and the egg.
Mix to combine. You may need a bit more water — add just a tablespoon at a time, mixing and gathering in the dough, until it comes together.
Using your hands, or the dough hook of a stand mixer, knead the dough until smooth and elastic.
Place in a lightly oiled bowl, oiling the top of the dough as well, and cover with a tea towel.
Leave to rise for about an hour until doubled in size.
Form the dough into 10 small sausage shaped logs.
Place on a well-oiled tray about 4cm apart (the dough will rise and spread)
Brush the top of the rolls with oil, cover the tray with a tea towel and let rise for another half hour.
Pour oil into a heavy-bottom frying pan or a deep fat fryer, heat to 180°C and fry the dough for about 3-5 minutes per side, until deep gold and cooked through.
Remove and drain on paper towel or a rack.
Meanwhile, mix the tuna, mayonnaise, parsley and seasoning.
Finely dice the potatoes.
Cut the boiled eggs into small pieces or coarsely grate them.
Mix eggs and potatoes and add a little salt.
Once cooled, slice open horizontally and serve fill with tuna salad, hard-boiled eggs, potatoes and olives.