These no-bake dessert treats are just bursting with bright citrus flavor! Just like your favorite summer slice of key lime pie, in marshmallow form!
Lightly mist a loaf pan with non-stick spray, and line with parchment.
Place the key lime juice in a large mixing bowl, and sprinkle the powdered gelatin on top. Set aside and allow to soften.
Combine the sugar, corn syrup, water, and salt in a medium saucepan, and set over medium-high heat. Allow the mixture to come to a boil, swirling the pot occasionally (do not stir). Attach a candy thermometer to the side of the pot, and keep the mixture at a low boil until it reaches 238 degrees F.
Increase the speed to high and continue to whip until the marshmallow is stiff, glossy, and white.
Stir in the vanilla extract and lime zest.
Turn the marshmallow out onto a cutting board, peel away the parchment, and use a sharp knife (misted with non-stick spray) to cut into 2-inch squares.