Combine the all-purpose flour, baking powder, and 1/2 teaspoon salt in a mixing bowl.

Add the melted unsalted butter and egg to the flour mixture.

Pour in the milk and mix until a soft dough forms.

Knead the dough for 5 minutes until smooth and elastic.

Cover the dough and let it rest for 20 minutes at room temperature.

Finely chop 1 onion and the red bell pepper for the tuna filling.

Heat 2 tablespoons sunflower oil in a frying pan over medium heat.

Cook the chopped onion and red bell pepper for 5 minutes until softened.

Stir in 2 tablespoons tomato paste and the canned tuna.

Season the filling with 1 teaspoon each of salt, black pepper, paprika, and chili pepper.

Cook the tuna filling for 3 minutes, then transfer it to a bowl to cool.

Finely chop the remaining onion and garlic for the dipping sauce.

Cook the remaining onion and garlic in the same frying pan for 3 minutes over medium heat.

Add 1 tablespoon tomato paste and 1/2 teaspoon each of paprika and chili pepper.

Add 1/2 teaspoon salt, 1 teaspoon black pepper, and the sugar to the sauce mixture.

Pour in the hot sauce and 120 ml water, then simmer for 8 minutes until thickened.

Divide the rested dough into 12 equal balls.

Roll each dough ball into a thin 12 cm circle.

Place about 1 tablespoon cooled tuna filling in the center of each dough circle.

Fold each dough circle into a half-moon and press the edges closed with a fork.

Heat the frying oil in a deep pot to 175°C (350°F).

Fry the filled pastries in batches for 3 to 4 minutes until deep golden brown.

Drain the fried fataya on paper towel and serve hot with the spicy tomato sauce.