Pure Vanilla Extract

So I have seen this on Pinterest. I have found that there is no exact recipe. So I started with 8 Madagascar vanilla beans and vodka. I did scrap the beans out of 3 of the pods to use for icing. A few of the post I found said to start with at least 4 pods full of beans. Then, every time you use a vanilla bean, put the empty casing in the bottle.  Shake it once a week. It will be ready in 8-12 weeks. The longer it sits, the stronger it gets.  Just top it off with vodka each time you use it and shake.