4 small boxes (3 oz. each) of Jell-O or store brand "gelatin dessert" in different colors. (I used strawberry, lime, orange and blue. My store only sells the big 6 oz. box of blue jello so I weighed 3 oz. or half of the package).
1 (14 oz.) can sweetened condensed milk (don't get evaporated milk)
2 envelopes unflavored gelatin (that Knox stuff)
Please note: Only add 1 cup of water to each box of colored Jello. Ignore the instructions on the box of Jello (they say to use 2 cups of water). Use only 1 cup of water so the Jello is firm and can be cut into blocks.
In a separate bowl, sprinkle 2 envelopes unflavored gelatin into 1/2 cup cold water. After the gelatin blooms, add 1 1/2 cup boiling water and dissolve. Add the can of condensed milk. Stir and cool. Pour cooled milk mixture over jello and chill overnight. (Although not shown here, it is a good idea to skim off the bubbles for a nicer finished product.)
The Food Librarian: http://foodlibrarian.blogspot.com/
Full color photos and instructions: Broken Glass Jello blog post (March 2, 2009): http://foodlibrarian.blogspot.com/2009/03/broken-glass-jello.html
Other Jello recipes on The Food Librarian: http://foodlibrarian.blogspot.com/p/jello.html
November 9, 2011: Broken Glass Jello Bundt: http://foodlibrarian.blogspot.com/2011/11/broken-glass-jello-bundt-day-24-of-food.html
Alternations: Increase packets of gelatin from two to three envelopes. Lightly oil the Bundt pan with canola oil and then wipe out 99% of it. After the bundt is refrigerated overnight, unmold by dipping the pan very briefly in warm water then invert onto a serving platter.