Remove the cereal from the box then use a rolling pin to break the cereal apart into small crushed pieces. Alternatively, add the cereal into a food processor and pulse until broken down into pieces. Spray a 13x9 inch rectangular pan with non-stick spray. Set it aside.
In a pot or large pan, add in the butter and allow it to melt. Mix in the marshmallows and stir until it melts and combines into the butter. Add in the vanilla extract and salt. Fold the crushed cereal into the marshmallow mixture until the ingredients are evenly combined. Quickly transfer the mixture to the 13x9 inch pan.
Coat your hands with cooking spray. Use your hands to press the mixture into the pan in an even layer. Allow it to cool to room temperature. Once cooled, invert the pan onto a cutting board. Remove the pan and cut the bar in half lengthwise. Then cut each strip into 8 bars so that you have a total of 16 rectangular bars.
Add the white chocolate chips into a small bowl. Microwave the chocolate for 30 seconds, and stir. Continue to microwave the chocolate in 15 second intervals, stirring after each session, until it has completely melted.
Transfer the melted white chocolate into a piping bag. Snip off the tip then drizzle the chocolate over the cereal bars. Before the chocolate hardens, add the sprinkles on top. Allow the chocolate to set before serving. Enjoy!