Preheat the oven to 350°F. Prepare a baking sheets by lining with parchment paper or a silicone baking mat. Set aside.
In a small bowl, whisk together flour and baking powder. Set aside.
In the bowl of a stand mixer {or in a large bowl using an electric beater}, cream together butter and sugar until fluffy. Add pudding mix and mix until combined.
Add eggs, one at a time, beating after each addition until fully incorporated.
Slowly add in flour mixture until just incorporated. Do not over mix. {At this point, you can also stir in any additional add-ins, mixing until fully distributed.} If plain cookies are desired, continue to next step.}
Using a small cookie scoop, scoop dough onto prepared baking sheet, leaving about 2 inches between each.
Bake for 10 to 12 minutes until cookies are set. Remove from oven and cool on baking sheet for about 5 minutes {they will be very soft and difficult to move if they're too hot}. Transfer to cooling racks.