Start by patting the grouper fillets dry with paper towels.
In a small bowl, mix together garlic powder, paprika, cayenne (if using), salt, and black pepper. Sprinkle this spice mix evenly over both sides of each grouper fillet.
Heat olive oil in a large skillet over medium-high heat. Once hot, gently add the grouper fillets to the skillet. Cook for about 3–4 minutes per side until golden brown and cooked through.
In the same skillet, reduce heat to medium and melt butter. Add finely diced onion along with minced garlic and grated ginger. Sauté until fragrant and softened—about 2–3 minutes.
Stir in red curry paste and turmeric powder; cook for another minute. Next, pour in coconut milk while adding lime zest, lime juice, diced pineapple, and honey if desired. Stir everything together until combined.
Allow sauce to simmer for about 5–7 minutes until it thickens slightly. Taste and adjust seasoning with salt and pepper as needed.
Return seared grouper fillets back into the skillet, spooning some spicy coconut sauce over them. Let everything cook together for an additional couple of minutes.
Garnish your dish with fresh chopped cilantro and sliced red chili if you like it spicy! Serve over steamed jasmine rice or coconut rice—and don’t forget those lime wedges on the side!