Oven Preparation: Commence by preheating the oven to a temperature of 375°F (190°C). Simultaneously, prepare a large baking sheet by lining it with parchment paper.
Dough Formation: Utilize either a hand-held mixer or a stand mixer to thoroughly combine the cake mix, butter, and eggs until a uniform mixture is achieved.
Adding Flavor and Color: Introduce the peppermint (or mint) and vanilla extracts into the mixture, followed by a judicious addition of green food coloring to attain the desired coloration. Continue to mix at a low speed until just combined, ensuring that the batter attains a thick and sticky consistency.
Coating Mixture Preparation: In a separate, smaller bowl, proceed to whisk together the powdered sugar and cornstarch.
Shaping Cookies: Employing a 1 1/2 tablespoon cookie scoop, shape the dough into balls. Roll each dough ball in the powdered sugar mixture to achieve an even coating. Bear in mind the inherent stickiness of the dough during this process. Arrange the coated dough balls on the prepared baking sheet, spaced approximately one inch apart.
Baking Process: Insert the baking sheet into the preheated oven, allowing the cookies to bake for a duration of 10 to 12 minutes. The criterion for completion is the cookies' edges becoming set and the tops appearing dry.
Final Touch: Promptly upon removal from the oven, adorn each cookie with a single heart-shaped sprinkle, gently pressing it to ensure adhesion to the cookie surface.
Cooling: Allow the cookies to rest on the baking sheet for a five-minute interval before transferring them to a wire rack for complete cooling. This step is crucial to maintain the structural integrity and textural quality of the cookies.