2 small, fresh mackeral
1 large grapefruit, green
1 small sweet onion, very finely chopped
2 teaspoons soft brown sugar
2 oz butter
1. Clean the mackeral.
2. Zest the grapefruit, then juice it. Reserve 4 thin slices of peel. Add an equal quantity of gin to the juice and zest. Marinade the fish in this mixture for a couple of hours.
3. Remove the fish from the marinade, and grill for about 5-8 minutes each side, depending on the size of the fish. (Until the flesh next to the bone is just opaque.)
4. Meanwhile fry the onion in the butter on a low heat until just golden. Add the marinade and sugar, and turn the heat up - simmer the sauce until it is thickish. Adjust seasoning, and thickness with orange juice / potato starch.