Combine butter and sugars in a large bowl and use an electric mixer to beat until creamy.

Add egg yolk and stir well.

Add salt, vanilla extract, and almond extract (if using). Beat until well-combined.

With the mixer on low-speed, gradually add flour until completely combined. Dough may be crumbly; if needed, use a spatula to scrape the bottom and sides of the bowl and work the flour into the dough.

Add nonpareils (if using) and fold into dough.

Divide dough into 2 parts and transfer each part onto a sheet of wax paper. Work dough into a 2" wide log shape and transfer to the refrigerator to chill for at least 2-3 hours.

Once dough has chilled, preheat oven to 350ºF (175ºC) and line a cookie sheet with parchment paper.

Remove one cookie dough log from the refrigerator and use a sharp knife to cut into ¼" slices.

Place slices on prepared cookie sheet about 1" apart and bake on 350ºF (175ºC) for 10-12 minutes or until edges are just beginning to turn golden brown.

Allow to cool on the baking sheet before serving.