1Finely chop the red onion, garlic, and bell pepper. Sauté in a little neutral oil over medium heat until softened, about 3-4 minutes.
2Add ground coriander and paprika, cook for 1 minute until fragrant.
3Add drained tuna, raisins, and ketchup. Cook for 2-3 minutes, breaking up the tuna with a spoon.
4Remove from heat and stir in chopped parsley or celery leaves. Let the filling cool slightly.
5In a large bowl, mix warm water, soft vegetable butter, and salt. Gradually add cornmeal, stirring with a fork until a soft, pliable dough forms.
6Divide dough into 8 equal parts. On a lightly oiled surface or between two sheets of parchment paper, press or roll each part into a thin disc (about 12 cm / 4.7 inches diameter).
7Place a generous spoonful of tuna filling on one half of each disc. Fold the other half over the filling to form a half-moon, and press edges firmly to seal. Crimp with a fork for a secure seal.
8Lightly brush or spray empanadas with neutral oil. Preheat air fryer to 180°C (350°F). Place empanadas in a single layer in the basket (work in batches if needed).
9Cook in air fryer for 10-12 minutes, turning halfway, until golden and crispy. Serve warm.