Preheat your oven to 350 degrees F and line a baking sheet with parchment paper. In a mixing bowl whisk the flour, cornstarch, baking soda, and salt together. Set aside.

In a separate bowl, beat together the butter, brown sugar, and sugar until light and fluffy.

Add the vanilla and egg and beat until combined.

Pour the dry ingredients into the brown sugar egg mixture and beat until combined.

Fold in the chocolate chips, butterscotch chips, M&Ms, pretzels, and toffee bits into the batter.

Use a cookie scoop or tablespoon to scoop the Christmas Kitchen Sink Cookie dough into balls. Place each dough ball onto the parchment lined baking sheet, leaving around 2 inches between each cookie to allow space for spreading.

Place in preheated oven and cook for 9 to 12 minutes, until the edges are golden brown and the center is still soft. Allow the cookies to cool on the cooking sheet for five minutes, then transfer them to a wire cooling rack to cool completely.