Place the raspberries in a food processor; cover and puree. Strain and discard seeds. Transfer puree to a large bowl. Stir in sugar and lemon juice; set aside.
In a small saucepan, sprinkle gelatin over cold water; let stand for 1 minute. Stir over low heat until gelatin is completely dissolved. Stir into raspberry mixture. Refrigerate until slightly thickened, about 1 hour.
Transfer gelatin mixture to a large bowl. Beat on high speed until foamy. Gradually add cream; beat until thickened, about 2 minutes. Spoon into dessert dishes. Cover and refrigerate until set, 1-2 hours.
If using frozen raspberries, use without thawing to avoid discoloring the batter.