I have a bottle of vanilla bean paste that says:
1 vanilla bean = 1 tsp vanilla bean paste
1 tsp vanilla bean paste = 1 tsp vanilla extract
So, according to this bottle, 2 vanilla beans would equal 2 tsp vanilla extract. But, I think vanilla is my secret ingredient in everything, add a little extra! I swear, people think I make magical rice crispy treats, but I just add vanilla extract to the marshmallows!