When baking something with raisins in it, how do you prevent the raisins on top from becoming like black burnt marbles?

i just made Irish Soda Bread and i put raisins in it. the raisins on top puffed up and got burnt looking. other than that the bread looks like it’s baked perfectly. i baked it at the temperature that the recipe called for. this has happened to me in the past. is there a way to prevent that from happening?