In medium bowl, thoroughly stir together the flour, baking powder, baking soda and salt; set aside.
In a large bowl with mixer on medium speed, beat together the brown sugar, butter, peanut butter, shortening and molasses until well blended and fluffy -- about 2 minutes. Add the eggs, and beat until very well blended and smooth.
Beat in half of the flour mixture until evenly incorporated. Stir in or beat in the rest of the flour mixture until evenly incorporated. .
Refrigerate the dough for at least 1 1/2 hours or up to 12 hours or until firmed up. Preheat the oven to 375*.
Grease several baking sheets or use nonstick spray.
Shape portions of the dough into generous 1 1/4" balls with lightly greased hands. Place the peanuts in a small bowl. Dip one half of each ball into the peanuts until some are embedded.
Place the balls, peanut side up on the baking sheets, spacing about 2 3/4" apart. Using your palm, press down on the balls until the tops are just flattened.
Bake the cookies, one sheet at a time in the upper third of the oven for 8-10 minutes or until lightly tinged with brown and just barely set when pressed in the centers. Reverse sheets halfway through baking from front to back to ensure even browning.
Transfer the sheets to a wire rack and let stand until the cookies firm up slightly. 1-2 minutes.With a spatula, remove cookies to wire racks to cool completely.
Store in an airtight container for up to 10 days or freeze up to 2 months.