Preheat oven to 350F/180C degrees. Butter a 9x13-inch pan or line with parchment paper.

In a medium bowl sift together flour, baking powder and salt. Set it aside.

In a stand mixer fitted with the paddle attachment, beat together butter,peanut butter and sugar for a few minutes until light and fluffy. Scrape down the sides and the bottom of the bowl. Add the eggs one at a time until combined. Stir in the vanilla. Stir in the flour mixture and beat slowly or fold by hand just until mixed . Add the chocolate covered pretzels and stir.

Scrape the dough into the prepared pan and smooth the top. Sprinkle some more chocolate covered pretzels on top if you like. Bake for about 30 minutes until a toothpick inserted into the center of the bars comes out clean. Let the bars cool completely and only then cut into squares.