In a large bowl, use an electric mixer to cream together the butter and sugars until light and fluffy.
Add the egg and vanilla and mix well until combined.
Add the flour, salt, baking powder, and baking soda to the sugar/butter mixture and mix well.
Use your hands to squish cookie dough into a ball. Cover and refrigerate for about 3 hours.
Take the dough out of the refrigerator and divide into two equal portions.
Preheat oven to 350F. Rinse Handi-Foil Cookie Sheet, wipe it dry, and set aside.
On a floured surface roll dough out about ¼ inch thick and cut rounds with a 3-inch cookie cutter.
Place on prepared baking sheets.
Bake for 20-25 minutes, until the edges begin to turn golden.
Let stand on cookie sheets for 5 minutes before removing to wire racks to cool.
Combine the glaze ingredients in a small saucepan over medium heat stirring until smooth. Remove from heat and let cool about 5 minutes until thickened.
Put candy sprinkles into a shallow container.
Spread cookies with about 1 teaspoon of glaze each and dip them glaze side down into the sprinkles.
Place cookies on a wire rack for about 30 minutes to allow the glaze to set.