Process raspberries in a blender or food processor until smooth. Pour through a wire-mesh strainer into a bowl, discarding seeds; set aside. (Pulp and liquid should equal about 1 1/2 cups.)
Stir together lemon juice and 1 tablespoon cold water; sprinkle gelatin over lemon juice mixture. Stir and let stand 1 minute; set aside.
Whisk together 1 cup raspberry puree, granulated sugar, eggs, and egg yolks in top of a double boiler. Bring water to a slight boil in bottom pan; reduce heat to low, and cook, whisking constantly, 20 minutes or until mixture thickens and reaches 160°. Remove pan from heat.
Whisk gelatin mixture into raspberry puree mixture in pan, whisking constantly, 1 minute and 30 seconds or until blended.
Whisk in remaining 1/2 cup raspberry puree and raspberry liqueur; chill 30 minutes or until consistency of unbeaten egg white.
Beat whipping cream until foamy; gradually add powdered sugar, beating until soft peaks form. Fold in raspberry mixture. Pour into a lightly greased 6-cup mold; cover and chill 8 hours or until firm. Unmold onto a serving dish.
*1 (10-ounce) package frozen raspberries, thawed, may be substituted.