Line a rimmed 14x10 inch or a 13x9 inch pan with parchment paper.
Split the marshmallows lengthwise.
In a large saucepan, melt the white coating over low heat, stirring often. Add chocolate and continue stirring on low to medium low until chocolate is melted. Stir in the peanuts.
Spread a thin layer of the chocolate mixture onto the parchment paper, then press the marshmallows side-by-side into the chocolate. Scrape remaining chocolate peanut mixture over the top and smooth it out with the scraper.
Chill (or freeze) until set. Lift from the pan and cut into squares.
Note: Next time I make this I might try adding the peanuts AFTER spreading the thin layer of chocolate over the bottom. It worked fine the way it’s written, but it might look nicer with a flat peanut-free base.