In a large mixing bowl, combine powdered sugar, peanut butter, softened butter, and vanilla extract. Stir until smooth and well combined.
Gently fold in the rice cereal, ensuring the mixture is evenly coated.
Press the mixture firmly into a greased 9x13-inch baking dish, spreading it into an even layer.
In a microwave-safe bowl, add chocolate chips and vegetable oil. Microwave in 30-second intervals, stirring in between, until fully melted and smooth.
Pour the melted chocolate over the rice cereal mixture, spreading it evenly.
Sprinkle the pastel-colored candy-coated eggs on top, pressing them slightly into the chocolate.
Refrigerate for at least 1 hour or until firm.
Once set, cut into squares and serve.