I'm making a raspberry filling for a wedding cake due Saturday. The recipe I have calls for frozen raspberries and I have fresh. They get cooked in the first step. Is there any reason I can't use the fresh ones?

I only have two thoughts. Maybe the frozen raspberries have preservatives in them? Or perhaps it's because frozen raspberries are cheaper than fresh?

1. Frozen raspberries might be available in many areas
2. Frozen raspberries also will have a higher water content than fresh.

Either of these reasons could be why frozen is suggested. If you have or want to use fresh, you might need to adjust the liquid called for in the recipe (if there is any)

You can use either, but I generally use frozen because they are cheaper and available year-round, and more consistent. I wanted my filling to be the same every time, so I just stuck with frozen berries all the time.

If you use fresh, you will have to make little adjustments every time, due to the much wider variation in water content and tartness of fresh berries.