Generously grease 13x9 baking pan or coat with nonstick spray.
In a large, heavy saucepan, thoroughly stir together the peanut butter, brown sugar, butter and corn syrup. Bring to a boil, over medium high heat and boil, stirring constantly for 1 minute. Remove from the heat.
Stir in corn flakes, 2/3 cup of the peanuts, the coconut, if using, and vanilla until evenly incorporated. Turn out the mixture into the baking pan, spreading to the edges.
Immediately sprinkle the chocolate mini morsels over the top, let stand until they melt. Using a table knife, spread the melted chocolate evenly over the top.Sprinkle the remaining 1/3 cup of peanuts over the chocolate.
Refrigerate until the chocolate completely sets, about 30 minutes.or freeze 15 minutes to speed chilling. Using a large, sharp knife, cut into 24 bars.
Store in an air tight container for up to 1 week for freeze up to 1 month.