01 -
Position an oven rack in the top and bottom thirds of the oven and preheat to 350°F. Line two baking sheets with parchment paper. In a medium bowl, whisk together flour, baking powder, kosher salt, and baking soda.
02 -
In a stand mixer fitted with the paddle attachment, beat butter, light brown sugar, and granulated sugar on medium-high speed until light and fluffy, approximately 1 to 2 minutes.
03 -
Add eggs one at a time along with vanilla extract; continue beating on medium speed until fully combined, about 1 to 2 minutes.
04 -
Add flour mixture to the butter mixture and beat on low speed, scraping the bowl once, until just combined, approximately 1 minute.
05 -
Mix in oats, candy-coated chocolates, chocolate chips, half of the sprinkles, and pecans (if using) on low speed until evenly distributed, about 30 seconds.
06 -
Spread remaining sprinkles in a shallow bowl. Using a 1/4-cup scoop, portion dough, roll into balls, and lightly flatten. Press the top of each ball into the sprinkles, place six dough balls per baking sheet, and top each with two candy eyeballs. Refrigerate remaining dough while baking batches.
07 -
Bake cookies at 350°F for 15 to 18 minutes, rotating pans halfway through baking, until edges are crisp and golden. Transfer pans to wire racks to cool slightly before moving cookies to racks to cool completely. Repeat with remaining dough after baking sheets cool.