1. Line two large baking sheets with parchment paper or silicone baking mats and set aside. Drain the maraschino cherries very well, spread them on paper towels, and pat completely dry. Chop the cherries into small pieces.

2. In a medium bowl, whisk together the all-purpose flour, baking soda, cornstarch, and fine sea salt until well combined.

3. In a large mixing bowl, beat the softened unsalted butter, light brown sugar, and granulated sugar with a hand mixer or stand mixer on medium speed for 2–3 minutes, until light and fluffy.

4. Add the egg and egg yolk one at a time, mixing well after each addition and scraping down the bowl as needed. Beat in the vanilla extract and maraschino cherry juice until smooth and creamy.

5. Turn the mixer to low and add the flour mixture in two additions, mixing just until no dry streaks remain and the dough has come together.

6. Use a spatula to gently fold in the chopped maraschino cherries, semisweet chocolate chips, and mini chocolate chips (if using) until evenly distributed.

7. Cover the bowl and refrigerate the dough for at least 30 minutes, or up to 24 hours, to help the cookies bake thick and chewy.

8. When ready to bake, preheat the oven to 350°F (175°C). Scoop about 1 1/2 tablespoons of chilled dough per cookie and place on the prepared baking sheets, spacing the scoops about 2 inches apart.

9. If desired, press a few extra chocolate chips and cherry pieces onto the tops of the dough mounds for a bakery-style look.

10. Bake for 10–12 minutes, rotating the pans halfway through, until the edges are set and lightly golden but the centers still look slightly soft.

11. Allow the cookies to cool on the baking sheets for 5 minutes, then transfer them to a wire rack to cool completely. Serve warm or at room temperature.