Grilling oysters for a few minutes allows them to open up easily. Once opened, top the oysters with a spicy-sweet grapefruit and bell pepper relish and return to the grill to be heated through.
For the relish, heat oil in a medium frying pan on medium-high heat. Add onion and garlic, cook and stir for 3 minutes or until softened. Add ½ of the grapefruit segments and bell pepper, cook and stir for 30 seconds. Remove from heat and stir in honey, Basil, Salt and Red and black pepper mix then set aside.
Grill oysters, flat-side up, over a medium-high heat for 3 - 5 minutes or until oysters begin to open. (Discard any oysters that do not open). Remove oysters from grill with spatula or tongs, removing top shell. Loosen oysters from the bottom shells with a paring knife.
Top each oyster with 1 tsp of relish and 1 of the remaining grapefruit segments, grill the oysters for a further 3 to 5 minutes or until heated through. Sprinkle with parsley and serve immediately.