Creamy Knox Blox 3 small boxes gelatin (same flavor) 4 envelopes Knox gelatine 3 cups boiling water 1/2 pint heavy cream Combine gelatin and Knox gelatine in bowl. Dissolve in hot water. Add heavy cream and stir until well mixed. Pour into a shallow 13 x 9-inch pan. Place into refrigerator to set. Cut into cubes.