Line a 9 x 13-inch baking pan with parchment paper and lightly spray with oil. Set aside.
Plant-Based Oil Spray
In a large pot, melt the plant-based 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.
3/4 cup plant-based butter, 2 bags 10-oz vegan marshmallows*
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.
1/2 tsp pure vanilla extract, 8 cups rice 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!