When faced with my husband's question of why, exactly, I was making our own vanilla, the only answer I could come up with at the time was that I could.
A better answer would have been to explain to him that I like the idea of going back as many steps as possible when making food from scratch, and that going back and making as much as possible at home increases the transparency of what is in the food and makes it simpler for your body to digest.
Anyway, I found a few recipes (Caveman Keto and The Prairie Homestead) and they basically seemed the same.
Slice a vanilla bean in half, put it into a glass bottle, and pour vodka or bourbon over it and let it sit. Times vary from 6 weeks to 6 months in the recipes; I will smell mine at 6 weeks and see. We chose bourbon because we are used to using bourbon vanilla and, if faced with any leftover, we prefer bourbon to vodka.
Label it if you want. Shake it every so often.
Looks like when it is ready, you can leave the used bean in there and re-fill it with alcohol and let it sit again (and re-use the bean indefinitely). Or take the bean out and give the bean a second life in your sugar storage bin making vanilla sugar.