Line a large 9x9 glass baking dish with parchment paper, set aside. Also set aside about 1/2 cup of mini marshmallows, these will be used later in the recipe.
In a large pot, add the dairy free butter and the rest of the marshmallows on low heat. Stir for about 5 minutes until butter and marshmallows have completely melted.
Add the vanilla extract to the butter and marshmallows and stir well to combine.
Add the rice cereal and the extra 1/2 cup of marshmallows to the pot and stir to combine.
Pour the rice cereal into the baking dish - and gently press the rice cereal down. Make sure to not pack down too hard, as the looser they are placed in teh baking dish the softer they will be.