Combine biscuits and butter in bowl. Press evenly over base of prepared pan; refrigerate until firm.
Combine marshmallows, gelatine and milk in saucepan, stir over low heat, without boiling, until marshmallows are melted. Transfer to large bowl, add essence; cool to room temperature. Whip cream until soft peaks form, fold into marshmallow mixture, pour over base. Place strawberries over marshmallow; refrigerate mixture 30 minutes.
Dissolve jelly into boiling water; cool to room temperature. Pour jelly over strawberries, refrigerate until firm before cutting.