Frozen Tropical Terrine with Mango-Blackberry Sauce

Line 9x5x2 3/4-inch metal loaf pan with 2 layers of plastic wrap in each direction, leaving overhang.

Sprinkle 1 1/4 cups toasted coconut over bottom of pan. Microwave 1 pint pineapple-coconut ice cream on low in two or three 10-second intervals until slightly softened. Drop ice cream by large spoonfuls over coconut in pan, then spread in even layer; freeze 15 minutes. Microwave mango sorbet on low in two or three 10-second intervals until slightly softened. Drop sorbet by large spoonfuls atop ice cream, then spread in even layer; freeze 15 minutes. Repeat with boysenberry sorbet, then remaining 1 pint ice cream.

Sprinkle remaining coconut over top; press to adhere (filling will extend slightly above pan). Cover with plastic wrap overhang; freeze overnight. (Can be made 3 days ahead. Keep frozen.)

Combine mango, blackberries, and sugar in medium bowl. Scrape in seeds from vanilla bean; add bean and toss.

Let stand at room temperature until juices form, tossing occasionally, about 2 hours. (Can be made 4 hours ahead. Cover and chill.) Discard vanilla bean.

Using plastic wrap as aid, lift terrine out of pan; remove plastic wrap.

Cut terrine into 3/4-inch-thick slices.

Place on plates; spoon sauce over and serve.