In the bowl of a stand mixer cream together 1 cup unsalted butter and 2/3 cup granulated sugar until well combined. Mix in 1/2 teaspoon almond extract and 1/2 teaspoon vanilla extract. With mixer set on low speed slowly add in 2 1/4 cups all-purpose flour and 1/2 teaspoon salt and mix until combined. Add in half of the 5 tablespoons sprinkles (set remaining half in small bowl) and stir to combine.
Press dough into a half inch thick layer on parchment lined baking sheet. Cover surface of dough with plastic wrap and chill in refrigerator for at least an hour (can be overnight).
To bake, preheat oven to 350 degrees F.
Cut dough into 1/2-inch squares using a large sharp knife. Gently press each cube into the bowl of sprinkles to get more to stick to the top. Set cubes on ungreased baking sheet (note: they won't spread much if the dough is cold so you can squeeze a lot on). Bake in preheated oven 8 - 12 minutes and cool baking sheet.
Store completely cooled cookies in an airtight container at room temperature.
Notes
Be sure the butter is softened prior to mixing. If your house is cold, you can soften the butter in the microwave on 30% power in 15 second increments.
You can omit the almond extract and replace it with additional vanilla, but I highly recommend using it for the flavor it adds.
Do not over mix the batter. The most tender cookies will come from minimally mixed cookie batter.
Any kind of sprinkles will work, but I prefer nonpareils (teeny-tiny balls).
Do not over cook these shortbread cookies. They will not brown, so you must trust the timer to know when they are done.