Whisk together the flour, baking soda, and salt. Set aside.
Using an electric mixer on medium speed, beat the butter and sugar until light and fluffy. Add the egg and both extracts, and mix until combined. Add the sour cream, and mix just until combined.
Reduce the mixer speed to low. Gradually add the flour mixture, mixing just until combined.
Cover and refrigerate the dough for 30 minutes.
Preheat the oven to 375°F (190°C). Line baking sheets with parchment paper or silicone liners.
Drop the dough by tablespoonfuls onto the prepared pans.
Bake one pan at a time for 8 to 10 minutes, or until the edges are golden brown and the centers are set.
Place the pans on wire racks and allow the cookies to cool for 5 minutes. Then transfer the cookies directly to a wire rack to cool completely.
To make the glaze:
Stir together the confectioners’ sugar, vanilla, and 2 tablespoons (30ml) of milk. Add more milk, a small amount at a time, as needed until the glaze is thick but spoonable.
Top the cookies with glaze. Top with sprinkles. Allow the glaze to set before serving.
Notes
Store in an airtight container at room temperature up to a week.