1. In a saucepan, melt the butter over medium heat.
2. Add the onion and sauté until translucent.
3. Add the garlic, carrot, and celery and cook for 5 minutes, stirring occasionally.
4. Stir in the chicken breast and tuna and cook until golden brown.
5. Add the fish stock, coconut milk, saffron, dried lime, salt, and pepper and bring to a simmer.
6. Reduce heat to low and cook for 15 minutes, or until the chicken is cooked through.
7. Serve hot, garnished with fresh herbs.
