In a bowl, combine the flour and baking powder. Set aside.
In another bowl, cream the butter and sugar with an electric mixer. Add the egg and beat until smooth. At low speed or with a wooden spoon, stir in the dry ingredients and the peanuts. Cover and refrigerate for 1 hour.
With the rack in the middle position, preheat the oven to 350°F (180°C). Line two baking sheets with parchment paper or silicone mats.
Shape the dough into balls using about 1 tbsp (15 ml) of dough for each cookie. Place the balls on the prepared baking sheets, spacing them evenly. With your fingers, slightly flatten each cookie.
Bake one sheet at a time for 10 to 12 minutes or until the cookies just begin to brown. Let rest for 5 minutes, then generously garnish each cookie with crushed chocolate peanut butter cups. Let cool completely.
The cookies will keep in an airtight container for 1 week at room temperature or 3 months in the freezer.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.