Stir together the flour, salt, and baking powder in a large bowl.
In a small bowl, mix together the rice milk and the vinegar.
Now add the milk mixture and the rest of the ingredients (sugar, banana, oil, raspberries, and strawberries) to the bowl with the dry mixture. You may need to mash the banana with a fork, depending on how soft it is.
Scoop the mixture into lightly oiled muffin tins, or use muffin liners. Fill the cups about 3/4 full. Bake for 35-45 minutes.