I usually like fresh fruits rather than frozen but make an exception for raw blueberries-- I actually prefer frozen because they are usually bigger, sweeter, and don't have any moldy/rotten ones in the mix. Being cheaper than fresh is a nice added bonus. Plus, they work awesome for pie filling! Forget the canned stuff or straining yourself with fresh berries-- this comes out tart but big on blueberry flavor, I like to use 1/8 cup Sun Crystals in place ofthe sugar. Arrowroot thickens quicker than cornstarch and aids digestion. Prep time does not account for defrosting the berries. This makes enough for one 9" pie.