Ingredients :

• Pure maple syrup — This is the ingredient that makes everything, so don’t skimp. Get Grade A dark (amber or dark), which is more intense on the palate than golden. Syrups labeled ‘maple aroma’ or ‘maple flavor’ produce a bland cream without character. You don’t need a big brand, but check that the ingredient list has only one item.
• Mini marshmallows — They melt much more evenly than large ones. If you only have large ones, cut them in half before putting them in the saucepan. They are the binder for the crust—without a homogenous melt, the cereal will crumble at the first slice.
• Heavy cream — Heavy, really. Light cream (15 or 18% fat) doesn’t hold up during cooking and results in a cream that is too liquid and refuses to set properly. Use at least 30% fat—it’s what gives that almost silky mouthfeel.
• Cornstarch — This is what thickens the cream without making it sticky or gelatinous. Two tablespoons are enough. Mix it directly into the cold mixture before heating—never into a already hot liquid, or it will form lumps that no whisk can fix.