Combine all of the ingredients except for the raspberries. Scoop into a jar or other lidded container. Top the mixture with the raspberries - if they're frozen they will have time to defrost.
Pop the lid on your container and place in the fridge for at least four hours, or preferably overnight. When ready, simply stick a spoon in and enjoy. You can also add extra crunchy toppings or a dollop of yoghurt or nut butter as well.
*"gluten free" oats are not available in all countries, as there are different regulations around what is gluten free. If you are in Australia you will find it very difficult to find gluten free oats, as technically you can't call oats "gluten free" in Australia. It's a very confusing topic and I will pop a blog post up about this eventually! For now I will say - if you are medically diagnosed coeliac, please be certain you can tolerate oats before you eat them. :)
*on a lighter note, my favourite additional toppings for these raspberry kefir overnight oats are a tablespoon of peanut butter and a sprinkle of pumpkin seeds!