Put the heavy cream, butter and sugar in a small pot or pan. (if using vanilla OIL you can add it now too. If extract, after cooking).

Turn heat on medium low. Bring to a boil while whisking continuously. After it starts to boil, simmer it for another 2-3 minutes (while whisking/stirring).

Stop heat and stir in the bourbon and vanilla extract. Pour into a small jar or cup and use immediately or save for later.

Pour over cakes, ice cream, etc. It will get stiff when cooling, so you will want to lightly heat it in the microwave if it is not runny enough.