Dissolve gelatin in boiling water. Place frozen strawberries in food processor, puree. Strain out seeds. Stir strained strawberries into dissolved gelatin. Allow to thicken slightly, about 1 1/2 hours. Whip cream; fold into strawberry mixture. Be sure to stir until smooth and mixed well.
Note: for a smooth mousse, add whipped cream as soon as gelatin begins to set; for chunkier look, let gelatin set a little longer, then add whipped cream. Pour into pan. Chill until set, unmold.