Creating Halloween Monster Cookies will be a breeze with these simple steps:

1. Preheat the Oven: Begin by preheating your oven to 350°F (175°C). Line a baking sheet with parchment paper or a silicone baking mat.
2. Cream the Butter and Sugars: In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.
3. Add Eggs and Vanilla: Beat in the eggs, one at a time, followed by the vanilla extract. Mix until well combined.
4. Combine Dry Ingredients: In another bowl, whisk together the flour, baking soda, and salt.
5. Mix Dry and Wet Ingredients: Gradually add the dry ingredients to the wet mixture, mixing on low speed until just combined. Be careful not to over-mix.
6. Stir in Oats and Chocolates: Fold in the rolled oats, chocolate chips, and Halloween-themed candies. Ensure they are evenly distributed throughout the cookie dough.
7. Scoop the Dough: Use a tablespoon or a cookie scoop to portion out the dough onto the prepared baking sheet, spacing them about 2 inches apart.
8. Optional Decoration: If desired, press extra candies into the tops of the cookie dough before baking for added visual appeal.
9. Bake the Cookies: Place the baking sheet in the preheated oven and bake for 10–12 minutes, or until the edges are lightly golden. The centers may look slightly underbaked; this is okay as they will firm up while cooling.
10. Cool the Cookies: Remove from the oven and allow the cookies to cool on the baking sheet for 5–10 minutes. Transfer them to a wire rack to cool completely.

These simple instructions will guide you to create the most amazing Halloween Monster Cookies!