A question about a recipe: All I Want For Christmas Peanut Butter Cookies

Don't hesitate to substitute. As Jessica said, use vanilla bean where it will really shine.

I only really mind doing this when it will MATTER (i.e. vanilla ice cream, vanilla yogurt, vanilla cookies...you see where this is going). If the vanilla is not the star flavor or doesn't need to be strong (caramel is a good example in my opinion), then extract works

totally fine. one teaspoon.