Heat oil. Add onion, bell pepper and celery. Saute for a few minutes.
Add garlic and continue to saute until the vegetables are softened.
Add tomatoes, capers, raisins, ketchup, mustard, chili paste. Simmer for about 5 minutes until the tomatoes are soft.
Add tuna and break it up into smaller pieces.
Cook for about 5 minutes until everything is heated through and well combined.
Add a generous sprinkling of black pepper and scant amount of salt.
Add parsley. Stir to combine and cook for 1 more minute. Let cool.
Preheat oven to 350 F.
Spray 10 ramekins with non stick cooking spray. Alternately, you can bake it in 1 pie plate.
Place cheese slices along the bottom and sides of the dish, overlapping the slices, making sure there are no spaces.
Place a few tablespoons of filling in each ramekin.
Cover with more cheese slices, again making sure there are no spaces.
Brush the top liberally with the egg to seal, especially at the edges.
Repeat until all the ramekins are stuffed.
Bake for 30 minutes.