Pour most of the half & half into your mason jar. Add the sugar and vanilla extract. (Note: I use 1/8 cup sugar because I prefer a less sweet coffee, but if you prefer it sweeter, use up to 1/4 cup sugar.)
Secure the lid tightly and shake until sugar dissolves.
Add the rest of the half & half and shake gently once more. (Adding the last bit at the end just helps avoid spilling.)
Keep the vanilla sweet cream stored in the refrigerator. Your homemade vanilla sweet cream is ready whenever you are. Just give it a quick shake before adding it to your coffee.