Line a 9 x 13 inch baking pan with parchment paper and lightly spray with oil. Set aside.
In a large pot, melt the vegan butter. Now add the vegan marshmallows and stir, until the marshmallows are melted. They won't melt as well as regular marshmallows, but they should still melt and turn into sort of a big blob.
Remove the pan from heat and stir in the vanilla. Now fold in the cereal using a large spoon or spatula. There will be chunks of marshmallows and that's okay, just try to coat all the cereal.
Transfer to the prepared pan and press down evenly either with your hands or a spatula. You can lightly grease the spatula if it sticks.
Allow the treats to cool for 1 hour. Remove from the pan, using the parchment paper, then cut into squares and serve. Enjoy!
Keep leftover treats in a covered container for up to 3 days. They do not freeze well.
I used Trader Joe's brand of marshmallows, but Dandies brand works as well.
Kellog's Rice Krispies are technically not vegan due to Vitamin D3 (which is made from animals), but Nature's Path work quite well and are gluten free!