Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, cream together the softened salted butter, dark brown sugar, and light brown sugar until smooth and fluffy.

Add in the two large eggs and one egg yolk, mixing well after each addition, then stir in the vanilla extract.

In a separate bowl, whisk together the all-purpose flour, baking soda, baking powder, and kosher salt. Gradually add this to the creamed mixture, mixing on low speed until just combined.

Fold in the old-fashioned oats, then carefully add the Halloween M&M’s, crushed mini pretzel sticks, and semi-sweet chocolate chips.

Scoop out dough portions using a 1/4 cup measuring cup and roll them into balls, spacing them 3 inches apart on the baking sheet.

Bake for 8 minutes, then rotate the baking sheet and bake for an additional 2 minutes until edges are golden.

Press extra M&M’s and candy eyes into the tops of cookies before the final baking.

Return to the oven for 2-3 minutes until golden at the edges but slightly soft in the center.

Cool on the baking sheet for 10 minutes before transferring to a wire rack.