Preheat oven to 375F (190C).

Combine butter, sugar, vanilla extract, and salt and beat with a stand mixer or an electric mixer until light and fluffy.

Stir in egg yolk and scrape down the sides of the bowl using a rubber spatula to ensure ingredients are well-incorporated.

In a separate bowl, whisk together flour and cornstarch.

With mixer on medium-low speed, gradually add flour mixture in 3-5 parts, stirring until almost completely combined before adding more. You will need to occasionally scrape the sides and the bottom of the bowl several times for this, as the mixture is fairly dry and crumbs tend to settle at the bottom of the bowl. Stir until all ingredients are combined and dough is beginning to cling together.

Stir in mini chocolate chips.

Pour your coarse sugar into a shallow dish (I used a plate for ease of rolling) and set nearby.

Scoop a level tablespoon of cookie dough and roll it into a tight, smooth ball.

Lightly flour your hands and, using your palms (not your fingers or the sticks will be lumpy), gently roll the dough out until it is about 6" long.

Briefly roll your cookie "stick" in the coarse sugar on the plate, and transfer to a wax paper lined plate or baking sheet. Make sure the stick is as straight as possible.

Transfer to your freezer and freeze for at least 15 minutes (to help keep the cookies from spreading). Meanwhile, preheat oven to 375F (190C).

Once oven is preheated and dough has chilled, remove cookie sticks from the fridge and carefully place on an ungreased cookie sheet, spacing at least 1-2" apart. Bake on 375 (190C) for 14 minutes or until edges are beginning to turn golden brown (do not place any subsequent batches of dough on hot pans or they will melt and spread).

Allow cookies to cool completely before dipping in chocolate.

If desired, once cookies are cooled dip in melted chocolate and decorate with sprinkles.

Allow chocolate to cool and harden before serving.