In a large bowl, beat together butter and sugars until light and fluffy. Beat in egg and vanilla until smooth.
In another bowl, sift together flour, baking soda, and salt. Mix into the wet ingredients, stopping halfway through mixing to add in the Halloween sprinkles. Continue to mix until dry ingredients are fully incorporated.
Use a medium cookie scoop to scoop cookie dough onto a lined baking sheet. You can place them close together for chilling. Chill dough in the refrigerator for 1 hour.
Preheat oven to 350°F and line two baking sheets with parchment paper.
Remove dough from fridge and arrange on the baking sheets, leaving space between to allow the cookies to spread without touching.
Bake for 12-14 minutes, until edges are golden brown. Let cool on the baking sheet briefly, then remove to a wire rack to cool completely.
Notes
Makes 12 big cookies.
If you prefer smaller cookies with a medium cookie scoop (1 1/2 tablespoons), reduce baking time to 10-12 minutes.
Nutrition information is an estimate based on online calculators and provided as a courtesy. Any nutritional information should be used as a general guideline only.