Believe it or not, I actually had to do 10 versions of this recipe before I found one that I was confident would work well for you all. A huge part of that was battling the fact that the raspberries released a lot of water during the bake. But I still wanted to still use those fresh berries for their amazing flavor. The solution to make sure you had a stable batter, that would produce great results and not get stuck in the pan, was to make a raspberry batter where we could offset the raspberries juices with that extra 1/4 cup of flour. Because of that dynamic, I don't recommend reverting to just adding raspberries to an all vanilla batter. I think you'll find, that'll result in a really dense, even rubbery underbaked cake.