In a big mixing bowl, whisk together peanut butter, agave, vanilla, sugar, and salt.
Stir in the crushed cornflakes until they are evenly coated in the peanut butter mixture.
Line an 8x8 or 9x9 inch pan with parchment paper. Spread the cornflake and peanut butter mixture evenly into the pan and freeze for at least 2 hours (or overnight).
After freezing, remove from the pan and slice into 18 rectangular bars. For optimal results, wait an hour before coating them in chocolate.
Melt chocolate with coconut oil using a double boiler or in the microwave, stirring in 30-second intervals until fully melted.
Use two forks to coat each bar in melted chocolate. Ensure thorough coating and let the excess chocolate drip back into the bowl.
Transfer the bars to a parchment paper-lined tray and top with crushed cornflakes and peanuts (optional).
Return to the freezer for 30 minutes to let the chocolate firm up. Remove from the freezer and indulge!