1-Using a stand mixer with a paddle: Using a stand mixer with a paddle attachment or hand mixer, cream together 1 cup butter and ⅔ cup granulated sugar for a few minutes. The mixture should be light and airy.
2-Add 1 egg and 1 tsp vanilla: Add 1 egg and 1 tsp vanilla extract. Mix it again until well combined.
3-Add 2 cups all-purpose flour and ¼: Add 2 cups all-purpose flour and ¼ tsp salt and mix on low speed until just combined.
4-Add 2 teaspoons milk and mix: Add 2 teaspoons milk and mix. The dough should be a pipeable consistency but not runny. You can add more milk if needed, but try to use as little milk as possible.
5-Transfer the dough to a piping bag: Transfer the dough to a piping bag with a large piping tip.
6-Pipe 2-inch swirls on a baking sheet: Pipe 2-inch swirls on a baking sheet (don’t use parchment paper!), 3 inches apart.
7-Place the baking sheet with piped cookies: Place the baking sheet with piped cookies in the fridge for 15-20 minutes. This extra step will help them keep their shape while baking.
8-Preheat the oven to 350°F: Preheat the oven to 350°F.
9-Bake the cookies for about 15 minutes: Bake the cookies for about 15 minutes or until they are golden brown on the sides.
10-When done, remove from the oven and: When done, remove from the oven and let them sit on the baking sheet for about 10 minutes, then transfer to a wire rack to cool off completely.
11-While they are cooling off, we can: While they are cooling off, we can prepare the chocolate. You can melt it on a double boiler or in a microwave. Put the chopped chocolate in a medium heat-proof bowl and microwave in 20 seconds increments, stirring after each increment.
12-Dip ⅔ of the cookies into melted: Dip ⅔ of the cookies into melted chocolate and place on a parchment paper. Decorate with sprinkles and let them dry off completely.