|Unflavored gelatin||6 Ounce (2 Envelopes)|
|Orange juice||1 1⁄4 Cup (20 tbs)|
|Sugar||1⁄4 Cup (4 tbs)|
|Grapefruit sections||4 Cup (64 tbs) (About 6 Pink Ones)|
|Orange sections||2 Cup (32 tbs) (About 6 Of Them)|
|Unsweetened frozen raspberries||12 Ounce, thawed (1 Package)|
|Orange sorbet||3 Cup (48 tbs)|
Sprinkle gelatin over orange juice in a small saucepan; let stand 1 minute.
Add sugar; cook over low heat, stirring until sugar and gelatin dissolve.
Remove from heat; let cool slightly.
Line an 8 x 4-inch loaf pan with plastic wrap.
Pour 1/4 cup gelatin mixture into loaf pan; chill to the consistency of unbeaten egg white.
Arrange 1/3 cups grapefruit sections over gelatin layer, overlapping slightly.
Pour 1/4 cup gelatin mixture over grapefruit layer; chill 10 minutes.
Arrange 1 cup orange sections over gelatin layer.
Pour 1/4 cup gelatin mixture over orange layer; chill 10 minutes.
Repeat layering with remaining grapefruit sections, gelatin mixture, and orange sections, ending with grapefruit sections.
Cover terrine with plastic wrap; press down lightly.
Chill 8 hours or until set.
Place raspberries in a food processor; process until smooth.
Strain through a sieve into a bowl, reserving 3/4 cup puree.
Invert terrine onto a platter; remove plastic wrap.
Cut terrine into 12 slices using a serrated knife.
Serve the terrine with raspberry puree and sorbet.
Garnish terrine with tarragon sprigs, if desired.