I make a vanilla porter and have always soaked them in vodka. Split, scrape and add the whole thing to secondary. I use 3 for a 5 gallon batch and it turns out great. You keep a lot more aroma with 3 than you do with 2.
On Tap: House IPA, Saison, Raspberry Cider, Amber Ale, Belgian Wit
Primary: Amber Ale
Bottles:Vanilla Porter, IC Milk Stout, Pale Ale
On Deck: West Coast Red, Saison, IIPA, IPA, American Farmhouse, Dubbel