In a mixing bowl, combine flour, water, salt, and olive oil. Mix until smooth and let rest for 10 minutes.

In another bowl, mix together the drained tuna, cottage cheese, parsley, lemon juice, and black pepper until well combined.

Heat a non-stick skillet over medium heat. Pour a ladle of batter into the skillet, spreading it out to form a thin circle.

Cook for about 2-3 minutes until the edges lift, then flip and cook for another 2 minutes.

Remove from skillet and repeat with remaining batter.

Place a spoonful of the filling on one half of each galette, fold over, and serve warm.