Using 1 tablespoon butter, grease the bottom and sides of an 8 by 8-inch baking pan.
To make the topping: In a small bowl, mash together the peanuts, flour, brown sugar, and a pinch of salt. Using your fingertips, mix in the butter. Set aside.
To make the bars: In a stand mixer, blend the butter, peanut butter, and brown sugar until light and creamy. Add the egg, vanilla extract, baking powder, and 1/2 teaspoon of salt in order, scraping down the sides as needed. Slowly blend in the flour then fold in the chocolate chips and shredded coconut. Press into the bottom of the prepared dish, then spread the jelly over the entire dish.
Sprinkle the reserved peanut topping over the top and bake until the edges and topping are golden brown, about 30 to 35 minutes. Allow it to cool before slicing.