
Butter a 9 x 13 inch (23x33 cm) baking dish and set aside.
In a large microwavable bowl add the marshmallows and butter and microwave for 1 minute at a time, stirring in between until fully melted.
Using a greased spatula, fold in the Fruity Pebbles, vanilla, and salt until the cereal is evenly coated.
Spread into your prepared baking dish and press down gently to create an even layer.
Let the treats set for 30 minutes before cutting into 12 squares.
Store in an airtight container at room temperature for up to 3 days.