- 2 cups milk
- 2/3 cup white sugar
- 3 tablespoons butter
- 2 teaspoons vanilla extract (optional)
- Turn slow cooker on High. Mix milk and sugar together in the crock of the slow cooker.
- Cook for 3 hours, stirring every 10 minutes in the last 30 minutes to prevent burning. Mix butter and vanilla extract into condensed milk and let cool.