Heat the coconut oil in a large high-sided skillet over medium heat. Add the minced onion and reduce heat to just below medium. Season with salt and black pepper, to taste, and stir to combine. Cook, stirring occasionally, until onions are a light golden brown, approximately 15-20 minutes.

While onions are cooking, combine coconut milk and tomatoes in a blender or food processor and pulse until just combined. (Small tomato chunks should still be visible). Set aside.

Once onions are golden brown, add ginger and garlic to the skillet and stir to combine. Sprinkle curry powder, chili powder, and cinnamon on top. Season with additional salt and black pepper, to taste, and stir to combine. Cook for approximately 1-2 minutes, or until very fragrant and a thick paste forms.

Pour coconut milk and tomato mixture into the skillet. Carefully scrape browned bits off the bottom of the skillet and stir until sauce is a rich golden color and the aromatic onion paste is thoroughly incorporated into the mixture.

Bring sauce to a gentle simmer and add the fish fillets. Cover and cook for 5 minutes before carefully turning the fish fillets over. Cover and continue cooking another 3-5 minutes, or until the fish is cooked through.

Remove from heat and stir in fresh lime juice and chopped cilantro. Taste and adjust seasonings, as desired. Serve immediately with basmati rice and/or roasted root vegetables. Offer additional lime wedges for squeezing, if desired. Enjoy!