In a large bowl, dissolve the gelatin completely in boiling water. Stir in frozen strawberries until they begin to thaw.

Blend the gelatin-strawberry mixture in a blender until smooth.

In a separate small bowl, mash the banana with lemon juice until smooth, then add to the blender.

Add sour cream and blend briefly—some texture is okay, but aim for a creamy consistency.

Pour mixture into a mold or dish, cover, and refrigerate for at least 3 hours (or overnight) until fully set.

To unmold, briefly dip the container’s bottom in warm water, then invert onto a serving plate. Garnish with fresh strawberries if desired.