First, make the marshmallows. Combine the powdered sugar and cornstarch together in a small bowl.
Line 8-inch square baking pan with plastic wrap and sprinkle the wrap generously with the powdered sugar and cornstarch mixture. Set the rest of the powdered sugar mixture aside.
Place the gelatin in an ice bath to soften.
Spray one side of the acetate with nonstick cooking spray, set aside (sprayed side up.)
Prepare a bain marie by placing a metal mixing bowl over a saucepan filled with just two inches of water over medium high heat.
Remove the gelatin from the ice bath and squeeze dry, place in prepared bain marie. Cook until the gelatin is melted, the reduce heat and keep warm.
Place egg whites in the bowl of a stand mixer fitted with the whisk attachment.
Combine sugar, water, corn syrup and vanilla extract in a large saucepan and bring to a simmer over medium-high heat. Stir to dissolve the sugar and then simmer an additional 5 minutes or so, or until the temperature reaches 250 degrees Fahrenheit.
Let the syrup continue to cook and turn the stand mixer on medium speed to start whipping the egg whites. The goal is for the egg whites to be forming medium peaks around the same time the syrup in the saucepan reaches 281-284 degrees Fahrenheit. Once the syrup reaches this temperature, remove it from the heat. If your egg whites start forming medium peaks before the syrup is done, lower the speed on the mixer slightly.
Add the syrup to the egg whites by slowly pouring it down the side as you have the mixer on low.
Pour in the prepared gelatin and increase the mixer speed to medium-high, about 5 minutes, or until mixture is thickened and glossy, warm but not hot.
Spray a spatula with nonstick cooking spray and use it to spread the marshmallow mixture into the prepared baking pan that has been lined with plastic wrap.
Top the spread out mixture with the prepared piece of acetate, sprayed side down, and gently press it down.
Let mixture stand at room temperature for a few hours to set.
Once mixture is cooled and set, remove the acetate and coat the top with the reserved powdered sugar mixture as necessary.
Spray a chef’s knife with nonstick cooking spray and cut the marshmallows into squares, cleaning and re-spraying the knife between each cut.
Coat the marshmallows with more of the powdered sugar mixture as needed so they are not too sticky.
Place marshmallows on a cookie sheet or two lined with parchment paper and freeze for at least one hour before dipping in caramel.
Once marshmallows are sufficiently frozen (this will help ensure they don’t melt into nothing as soon as you dip them in the caramel), start preparing the caramel.
Remove the wrappers from the caramels and add them to a small saucepan with the heavy cream over medium heat. Stir occasionally as the caramels melt.
Once the caramels and heavy cream have melted together and combined to form a creamy caramel, turn off the heat. Using two forks (or spoons, or a combo of both) dunk the marshmallows in so they are sufficiently coated. Place dipped caramels back on parchment paper-lined cookie sheets and refrigerate until caramel is hardened even to remove the kisses from the parchment paper.
Individually wrap the caramels in small pieces of parchment paper and keep refrigerated until ready to serve. (They can stand a short period of time at room temperature, but for longer periods be sure to keep them cool.)