1) Pour proper amount of milk (dairy or non-dairy, honestly water would work too) into bottle with just a little bit extra room
2) Pour milk from bottle into microwavable mug
3) Microwave until pretty hot but not boiling
4) Rigorously stir in in 1/2 a packet to a full packet of Carnation's Vanilla Breakfast Essentials meal replacement shake.
5) Add a few drops up to half a cap full of vanilla extract for added richness (You might also want to try adding small amounts of butter or cream)
6) Put back in bottle, make sure it won't burn your mouth before drinking, and at least rinse the bottle out when empty or the residue can get sticky and gross overnight
Very rich, very filling, heavenly. Especially if you only use half a packet per bottle instead of a full packet, it's not too caloric for how filling and rich it is.
I bought mine from a Kroger but I know Walmart carries it.
If you get clumps, make sure the mix is hot enough and that you're stirring strongly enough. I haven't had issues.
You can also just add a little vanilla extract to the milk of your choice, hot or cold, and forego the drink mix. But mixing it up feels like preparing a bottle to me.
It's just a treat for me now, but for a few days I drank three bottles of this a day, using only half a packet per bottle, and it was great. I just ate slightly lighter meals to make up for the added calories but I had no issue with that because drinking bottles of warm milk is incredibly filling.