- 3 12-oz cans of sweetened condensed milk
- 3 preserving jars with lids
- Pour the condensed milk into the jars, and seal very tightly.
- Pour hot (not quite boiling) water into your slow cooker to between 1/2 and 3/4 full, then carefully place your jars into the water and top up the water so that the jars are completely submerged, before cooking for 8 hours on low.
- It’s vital that the jars are submerged in the water during the whole cooking process, so keep checking the water level and top up if necessary.
- Let the jars cool down completely at room temperature before opening to avoid the glass breaking. The jars should be vacuum sealed, which you can check by pressing the lids. If the lid ‘pops’ when you press it, then use that jar straight away. Any jars with lids that stay firmly down when pressed are safe to store for up to four months.
Source : allrecipes.com