Preheat the oven to 350°F, line two baking sheets with parchment paper.

Mix together the flour, cornstarch, baking powder and salt. set aside.

Beat the butter and sugar together until light and fluffy.

Add in the corn syrup, egg, yolk, and vanilla until well-combined.

Add in the flour and sprinkles. Stir by hand until just combined.

Make balls of dough that are 1.5 tablespoons big. Chill for 10 minutes.

Place 2-inches apart on a baking sheet and bake for about 8 minutes. The cookies will look underbaked, this is normal.

Remove the cookies from the oven and leave it on the baking sheet for about 2 minutes before transferring to a wire rack.

Freeze the cookies for about 2 hours. Take about ⅓ cup of the ice cream and allow it to soften until almost completely melted.

Turn the cookies upside down and lightly brush the bottoms with the ice cream. Allow it to soak some of the ice cream.

Scoop ice cream onto half of the cookies, then top with the other half, immediately freeze until the ice cream looks nice and firm again. Place in airtight container.

To eat, wait about one minute for the cookie to soften slightly.