
Ingredients
1 1/2 cups  all-purpose flour
1 1/2 teaspoons  baking powder
1 teaspoon  salt
1 1/4 cups  tightly packed  light brown sugar
1 cup  creamy  peanut butter
1/4 pound  unsalted butter,  cut into 1-ounce pieces
1/4 cup  dark corn syrup
1 teaspoon  pure  vanilla extract
Ingredients for Topping:
3/4 cup  heavy cream
6 ounces  semisweet chocolate,  chopped into  ¼-inch pieces
1 cup  semisweet chocolate  chips
1 cup  peanut butter  chips
Preparation
1. Directions:
2. Preheat  the oven to 325 degrees.
4. In a sifter combine the flour,  baking powder,  and  salt.  Sift onto a large piece of wax paper and set aside until needed.
5. Place the light  brown  sugar, peanut butter, unsalted butter, and the corn syrup in the bowl of an electric mixer fitted with a paddle.  Beat  on medium for 4 minutes. Use a rubber spatula to scrape down the sides of the bowl, then  beat  on medium for 2 more minutes. Scrape down the bowl. Add the eggs, one at a time,  beating  on medium for 1 minute and scraping down the sides of the bowl after each addition. Add the vanilla  extract  and  beat  on medium for 1 minute. Operate the mixer on low while gradually adding the sifted  dry  ingredients until incorporated, about 1 minute. Add 3/4 cup shopped peanuts (the remaining peanuts are for the  topping)  and  beat  on medium for 10 seconds. Remove the bowl from the mixer and use a rubber spatula to finish  mixing  the i
6. Transfer the batter to a 9x13x2-inch nonstick  baking  pan. Use a rubber spatula to spread the batter in an even layer. Place the pan on the center rack of the preheated oven and  bake  for 35 minutes until a toothpick inserted in the center of the brownie comes out  clean.  Remove from the oven and allow to stand at room temperature for 1 hour before  finishing  with the  topping.
9. Pour the ganache over the  cooled  brownie. Use a cake spatula to spread the ganache evenly over the entire surface of the brownie.
10. Combine in a 3-quart bowl the chocolate chips, peanut butter chips, and the remaining 3/4 cup chopped unsalted peanuts.
11. Sprinkle the chips and nuts evenly over the ganche.  Refrigerate  the brownie for 1 hour before  cutting.  This will make the ganche layer firm enough to  cut.