In a large bowl, add in the butter, powdered sugar, granulated sugar, and vanilla if you’re using it. Beat on medium with an electric mixer until creamed.
Add in the flour, salt, and nonpareils. Mix until the flour is incorporated and a stiff cookie dough forms.
Divide the cookie dough into 2 pieces and press the dough flat. Wrap each piece in plastic wrap and place in the refrigerator for at least 30 minutes to chill.
Preheat the oven to 350°F. Line a cookie sheet with parchment paper or a silicone mat.
Roll the dough out to 1/4-inch thickness on a lightly floured surface. Cut out your cookies and place them on the prepared cookie sheet.
Bake for 10 to 13 minutes or until the edges are golden brown. (see notes)
Let the cookies cool for 5 to 10 minutes on the cookie sheet and then transfer to a wire rack to cool completely.
Store in an airtight container at room temperature.
Notes
The bake time can vary depending on the size of your cookie cutter. I recommend keeping an eye on the cookies at the 8-minute mark.
Feel free to add a drizzle of melted chocolate for added pizzaz.
You don't need cookie cutters for this recipe! You can use a knife and cut the cookie dough into sticks, rectangles, or square shapes.
To freeze dough:
You can wrap the dough in a couple of plastic wrap layers and then a layer of aluminum foil and place them in large freezer-safe ziptop bags for up to three months. When you are ready to bake, thaw the frozen dough overnight in the refrigerator before using it.
To freeze baked cookies:
Be sure the cookies are cooled completely before freezing! Line the bottom of an airtight freezer-safe container with freezer paper. Arrange an even layer of shortbread across the container's bottom, making sure the cookies do not overlap. Place another piece of freezer paper on top of the first layer. Add more cookies in an even layer, and cover with freezer paper. Repeat this process of layering until you fill-up the entire container. Ensure the top layer of shortbread is completely covered by the freezer paper, then cover it securely with the lid. Freeze for up to six months. To serve, allow the cookies to thaw to room temperature.