Preheat the oven to 350ºF (180ºC). Line a large cookie sheet with parchment paper.
In a medium-sized bowl, whisk together the flour, cornstarch, salt, baking powder and baking soda until well blended.
In a large bowl, beat the butter, granulated sugar and brown sugar, with an electric mixer at medium speed, until pale and fluffy. Beat in the egg and egg yolk in 2 separate additions until well incorporated. Beat in the extracts. On low speed, beat in the flour mixture, just until combined.
Divide the dough into 2 equal portions, using a kitchen scale for accuracy. Place the dough into 2 separate bowls. Mix the food coloring into one of the dough portions, a little at a time until your desired shade is achieved.
Place 3 tablespoons of sprinkles into a small, shallow bowl and set aside. Divide the remaining sprinkles in half. Mix each half of the sprinkles into the 2 separate dough colors.
Divide each color of dough into 16 portions, approximately 1 tablespoon each. Roll them into balls. Dip each dough ball into the reserved bowl of sprinkles, pressing gently to adhere the sprinkles to the bottoms of the dough balls.
Take 2 balls of each color of dough (4 total) and arrange them in a checkerboard pattern, sprinkle side up. Roll them together to form a large ball. Repeat this process to make 8 large dough balls. Form the dough balls into cylinder shapes and place them sprinkle side up onto the cookie sheet, about 3 inches apart. You may need to bake them in 2 batches.
Bake until the cookies are slightly puffed and the tops are set, about 10-12 minutes. Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a cooling rack.