Thanks, Marianne!
Great question. First let's talk about vanilla extract. This is a liquid concentrate. When you buy it at the store, be sure it is labeled as "Pure Vanilla Extract." Imitation vanilla flavor, blech!
With its concentrated flavor, a little bit of vanilla extract goes a long way. Something else to keep in mind: The extract of vanilla is almost always made with alcohol, so consider it when adding or substituting it in a recipe. Since most recipes only require a dash or a teaspoon though, the alcohol is something that you'll barely taste.
The vanilla bean to me, is a bit more versatile. First, the flavor is more precise.
Using it in a custard, like you say, the bean and its seeds are used to infuse flavor into the cream. This is done by splitting the bean in half and scraping the seeds from inside the pod with the back of a knife. Then, the seeds, along with the pod are placed in the liquid, usually milk or cream, and brought to a boil. The liquid can be cooled or used at this point. Usually the pods are removed and the seeds are left behind.
You can strain the seeds out with a fine mesh sieve or cheesecloth, but I like the added flavor and the look, so often I leave them in the sauce or custard.
The pods can be dried and then added to your sugar container, this will give you a great baking ingredient, vanilla sugar.
So you see, the vanilla bean has quite a life if you use it right. And since it is a somewhat expensive herb, we always want to get the most out of it.
Thanks for asking! And, as always: Keep Cooking!
Best,
Michael Reining
Chef / Host
The Radio Kitchen