Chocolate Peanut Butter Crunch Bars

From 6 Bittersweets
Adapted from Baked: New Frontiers in Baking via Making Life Delicious
Makes about 16 bars (9-inch square pan)

XIAOLU'S NOTES: To make cleaner slices, run the edge of your knife under hot water then wipe it clean before/between each slice. The heat will melt the chocolate so that it slices cleanly instead of cracking under the pressure of the knife.

Rice Krispies Base
3 1/2 cups crisped rice cereal (such as Rice Krispies)
1/2 cup sugar
6 Tbsp light corn syrup
1/2 cup water
6 Tbsp (3/4 stick) unsalted butter, cut into pieces
Large pinch of kosher salt

Peanut Butter Layer
6 oz. semisweet chocolate, coarsely chopped
*Alternately, you may substitute good quality white chocolate to allow the peanut butter flavor to stand out more
1 cup creamy peanut butter (NOT natural or old-fashioned)
2/3 tsp vanilla extract

Chocolate Topping
5 oz. dark chocolate (60% to 72% cacao), coarsely chopped
1 tsp light corn syrup
3 Tbsp unsalted butter
Large pinch of kosher salt

To prepare the base, line a 9-inch square pan with aluminum foil or parchment paper (base AND sides) then butter the foil/paper. Put the cereal in a large bowl and set aside.

Add the sugar, corn syrup, and water in a small to medium saucepan and stir until just combined. Don’t splash it around. You want to avoid getting sugar on the sides of the pan. Cook over high heat without stirring until mixture reaches the soft ball stage, 235 degrees F. You may have to tip your pan to get sufficient depth to register on a candy thermometer.

Remove from the heat, stir in the butter and a pinch of kosher salt. Then pour the mixture over the cereal. Working quickly, stir until the cereal is thoroughly coated, then press it evenly into the prepared pan using the flat bottom of a glass or slightly dampened fingers. Do NOT press down too much or the bars will be too hard. Let the crust cool to room temperature while you make the next layer.

To prepare the peanut butter layer, melt the chocolate and peanut butter together in a medium bowl over a saucepan of barely simmering water (basically a makeshift double-boiler). Stir until smooth. Remove the bowl from the pan to cool slightly, and stir in the vanilla. Pour the mixture over the cooled crust.

Put the pan in the fridge for 1 hour, or until the top layer hardens.

To prepare the chocolate topping, melt the chocolate, corn syrup, butter, and pinch of salt together in a medium bowl over a saucepan of barely simmering water. Stir until smooth. Remove the bowl from the pan and let it sit for a minute to cool slightly. Pour the mixture over the chilled peanut butter layer.

Spread evenly (a small offset spatula works well for this and it also helps to shake the pan gently from side to side to smooth out the surface). Put the pan in the fridge for 1 1/2 hours or until the topping hardens.

Cut into squares and serve. If there are any left, cover tightly and store for up to 4 days.