At home right now I have 2 jars of vodka that is infusing with marshmallow and coffee. I am quite excited to see what they turn out like.
Its a pretty basic process. Simply find a air-tight container (not plastic) and pick the flavor you would like. As I mentioned, I am doing one marshmallow and one coffee. Simply put some of whatever flavor you would like into the jar and fill with the vodka, close and give it a vigorous shake for 30 seconds.
Store in a cool place such as a cupboard or fridge. A few times a day, give it another shake. The amount of time you leave the flavoring in depends on how much flavor you would like. Simply open after 24hrs and take a small amount as a sample.
Once it is at the desired infusion, you have to strain the mixture. You can use a tea strainer with cheese cloth or a coffee filter. This may need to be done a few times depending on how much granules are left in the liquid, but the more you strain, the more flavor you run the risk of losing.
Once strained, store in a clean air-tight container such as a mason jar or flask and make sure to label it.
I plan on trying a caramel, and possibly a vanilla one next.