Put the cup of water in the freezer for 10 minutes. You can use either small or large molds. If you want to use a large mold, grease the inside with butter and leave the mold in the freezer until you’re ready to use it.
Take the water out of the freezer and add 1 tbsp. of gelatin, mixing it well until there are no lumps. Keep adding a spoonful at a time until finishing the mix. If you use powdered gelatin, add one packet at a time. (1½ oz.=4 tbsp.)
Once you have added the gelatin by the spoonful or by the packet, return the gelatin to the refrigerator to set while you prepare the rest of the ingredients. In the blender mix the cup of eggnog, the condensed milk, cow’s milk and vanilla.
Take the gelatin out of the refrigerator and microwave it for 20 seconds.
Mix it well and then return it to the microwave for another 20 seconds, until it’s liquid.
Pour the gelatin in the blender with the rest of the ingredients and blend it for 3 minutes. Fill your buttered baking pan with eggnog gelatin, put it in the refrigerator and leave overnight. Then take it out of the pan and serve.