To make the curry mix:
Combine all spices in a small bowl.
To make the corn-coconut curry sauce:
1. Heat 2 tablespoons of the butter in a medium sauté pan over high heat. Add the onion and apple and cook until soft, stirring occasionally, about 5 minutes. Add the garlic and cook for 30 seconds. Add the curry powder and cook for 2 minutes. Add the stock, bring to a boil and cook for 10 minutes. Strain the stock into a bowl and discard solids.
2. Heat the remaining 2 tablespoons of butter in a large high sided sauté pan. Add the corn and cook until golden brown. Add the stock and coconut milk and bring to a simmer. Cook until reduced and slightly thickened and the corn is tender, about 15 minutes. Season the sauce with salt and pepper and stir in the cilantro. Keep warm.
To make the grilled cherry tomato chutney:
1. Brush tomatoes with oil and season with salt and pepper and grill until charred and slightly soft.
2. Heat 2 tablespoons canola oil in a large sauté pan over high heat. Add the white and pale green part of the onion and the garlic and cook until soft, about 1 minute. Add the brown sugar, vinegar, 1/4 cup water, coriander, cumin and mustard seeds and cook for 30 seconds. Add the tomatoes and cook for 1 minute. Fold in the green onion. Let cool to room temperature. Yields 2 1/2 cups.
To prepare the grilled halibut:
Heat grill for direct grilling. Brush halibut with oil on both sides and season with salt and pepper. Grill until slightly charred and just cooked through, about 4 minutes per side. Ladle some of the sauce onto a platter and top the fillets and spoon more of the sauce over the top. Top each fillet with some of the tomato chutney and garnish with cilantro leaves.