I made these in August for Tony’s birthday and did NOT cut them into 48 tiny bars. I cut them into HUGE bars. Then I tried to eat one, went back, and cut them into 48 tiny bars. I used low-fat peanut butter, as always, and they still tasted good. We brought a bunch with on vacation and still had to give over half the batch away because we couldn’t eat fast enough to get rid of them. These seem like they taste better the day after you bake them, and continue to improve for the next few days provided you store them properly.

from Chocolate by the Cake Mix Doctor by Anne Bryn

1 package (18.25 ounces) plain yellow cake mix
1 cup chunky peanut butter
8 tablespoons (1 stick) butter, melted
2 large eggs
1 package (12 ounces; 2 cups) semisweet chocolate chips
1 can (14 ounces) sweetened condensed milk
2 tablespoons butter
1 cup frozen unsweetened grated coconut, thawed, or sweetened flaked coconut
2 teaspoons pure vanilla extract
1. Place a rack in the center of the oven and preheat the oven to 325 degrees F. Set aside an ungreased 13-by-9-inch baking pan.

2. Place the cake mix, peanut butter, melted butter and eggs in a large mixing bowl. Blend with an electric mixer on low speed for 1 minute. Stop the machine and scrape down the sides of the bowl with a rubber spatula. The mixture will be thick. Reserve 1 1/2 cups for the topping. Transfer the remaining crust mixture to the pan. Using your fingertips, press the crust evenly over the bottom of the pan so that it reaches all sides. Set aside.

3. For the filling, place the chocolate chips, condensed milk, and 2 tablespoons butter in a medium-size heavy saucepan over low heat. Stir and cook until the chocolate is melted and the mixture is well combined, 3 to 4 minutes. Remove the pan from the heat and stir in the coconut and vanilla until well distributed. Pour the chocolate mixture over the crust, and spread it evenly with the rubber spatula so that it reaches the sides of the pan. Using your fingertips, crumble the reserved crust and scatter it evenly over the chocolate. Place the pan in the oven.

4. Bake the cake until it is light brown, 25 to 30 minutes. Remove the pan from the oven and place it on a wire rack to cool for 30 minutes.

5. Cut the cake into 48 bars. Remove the bars from the pan with a metal spatula and serve.