Mix the honey, sucanat or raw sugar and milk in a saucepan. Bring it to a low simmer over medium heat - stirring often to prevent burning and to dissolve the sweetener. Watch for steam to begin rising from the milk. When the steam begins rising, lower the heat to as low as possible. A skim may form on top - just scoop it off.
Allow the mixture to reduce in volume by half. You can use a clean kitchen ruler to measure the amount. I could not find mine so I used a wooden popsicle stick, marked the level in the beginning and checked periodically until the level was half of what I started with. This step took 2 ½ hours.
When the amount is half of what you started with, whisk in the butter and vanilla.
Cool the sweetened condensed milk and use as desired or place in sterilized canning jars, put the lid on and place out of the way to allow it to seal. Finally, refrigerate any unused cans - they keep for several months.
Nutrition Information is for honey version.
A Few Tips For Making Homemade Sweetened Condensed Milk
The final color of the sweetened condensed milk will change based on the sweetener you use.
The sweetened condensed milk made with the sucanat actually started out darker than either of the other two while the honey-sweetened version became darker as it cooked.
I used raw wildflower honey which does not have an exceptionally strong taste to begin with. Also, I strained the honey-sweetened condensed milk for a smoother consistency.
Sucanat sweetened condensed milk sticks to the bottom of the pan much more quickly than the other two versions. So be sure to watch and stir!