Cover and refrigerate for at least 2 hours (can be overnight).
Preheat oven to 375° F.
Add and incorporate cranberries into refrigerated muffin mixture.
Add batter to 12 muffin cups (I use silicon cups but you can also use paper or a lightly greased muffin tin).
Bake muffins until golden, about 25-27 minutes.
Cool and remove muffins from muffin tin.
Eat immediately or refrigerate in a sealed container for up to 1 week. (I like to pop them into the toaster oven before eating, just to warm them up a bit.).