Preheat the oven to 375°F. Line two cookie sheets with parchment paper.
Cookie Dough: In the bowl of a stand mixer fitted with the whisk attachment, beat together the butter with the sugar on high speed until smooth.
Add the salt, vanilla extract, almond extract and egg yolk. Beat on medium-high speed for 2 minutes or until combined.
Switch to the paddle attachment. Add the flour on low speed, beating until combined. Stop and scrape the sides of the bowl periodically. Beat the dough until it's fully moistened. The cookie dough will be very thick.
Transfer the dough to a piping bag fitted with a large 1M open star pastry tip. Pipe the batter in a circular swirl pattern onto the prepared cookie sheet. Leave at least 2-inches of space between each cookie. (For less spreading, chill for 30 minutes on the pan.)
Bake for 8-11 minutes. The edges will be lightly golden brown and the cookie will appear “dry”.
Cool on the pan for 10-15 minutes before transferring them to a wire rack to cool completely. (Handle carefully, the cookies are fragile when they are warm.)
Melt Chocolate: Chop the chocolate into small pieces and place in a microwave-safe bowl with the shortening or coconut oil. Microwave at 50% power for 1 minute, then stop and stir. Repeat the process until completely smooth.
Dip one side of the cooled cookie into the melted chocolate. Sprinkle with nonpareils. Have nearby a pan lined with wax paper, lay cookies on the pan.
Let stand for 10-15 minutes or until the chocolate sets, then serve.