Preheat oven to 200°C.
Place flour, baking powder and salt in a large bowl. Mix well.
Add eggs one at a time.Pour in the milk and oil gradually, mixing at the same time. Add the drained olives, diced feta and comté cheeses, and drained and crumbled tuna.Cut the fresh onion into thin strips and add.Mix well, aerating the dough (by lifting it with a wooden spoon). Line your cake pan and pour the batter inside.
Bake for 40-45 minutes, checking for doneness.To do this, stick a clean knife into the cake; it should come out clean. Leave to cool on a wire rack before slicing and serving.
