1teaspooncoconut oildepending on your chocolate, you may need to thin it with coconut oil or vegetable oil
To a medium mixing bowl, whisk together the flour and salt. Set aside.
To a large mixing bowl, cream together the butter and sugar for two minutes. It should be light and fluffy.
Add in the vanilla extract and egg and beat an additional two minutes.
Pour the flour mixture into the butter mixture and beat until just combined.
At this point, you dough should be soft and pipeable. if your dough is too thick, add 1-2 tablespoons of milk and beat until combined.
Transfer half of the dough to the piping bag (or large freezer bag) fitted with a large tip (I use Wilton 4B star tip). Pipe the dough into swirls (approximately 1.5" in width) to a baking sheet. Place the baking sheet into the fridge to chill while you preheat the oven. Refill your piping bag with the remaining cookie dough and continue piping swirls onto an additional baking sheet and move that one to the fridge, as well.
Preheat the oven to 350° and bake the chilled cookies for 10-12 minutes or until just golden. They should not brown.
Remove the cookies from the pan to cool and melt the chocolate.
To a small microwave safe bowl, add the chocolate chips (and optional oil) and heat for 30 seconds, stir. Repeat as necessary until fully melted and smooth.
Dip the cooled cookies halfway into the chocolate and then lay onto parchment paper to set. Immediately sprinkle with nonpareils or your preferred sprinkle.
I used a Wilton 4B star baking tip.The more milk you add, the more your cookies will spread so keep that in mind as you pipe them. I recommend using Ghirardelli baking chips or a baking bar to melt. Traditional chocolate chips do not melt as nicely and you'll have to thin with oil.Store leftovers covered in an airtight container for up to a week.