Martha Stewart's Homemade Marshmallows

Pour ½ cup cold water into the bowl of an electric mixer fitted with the whisk attachment. Sprinkle unflavored gelatin over the water and let sit for 5 minutes to bloom.

Combine granulated sugar, light corn syrup, and salt in a medium saucepan. Cook over medium heat, stirring occasionally, until the mixture reaches 240°F on a candy thermometer (soft-ball stage).

Carefully pour the hot syrup into the mixer bowl with the bloomed gelatin while the mixer is running on low speed. Once combined, increase speed to high and whip for 12-15 minutes until the mixture becomes thick, pale, and nearly triples in volume.

Add pure vanilla extract to the marshmallow mixture and beat on high speed for 30 seconds to incorporate.

Prepare a 9-by-13-inch baking pan by lining it with parchment paper and dusting generously with confectioners' sugar.

Pour the marshmallow mixture into the prepared pan, using an offset spatula or damp hands to spread it into an even layer. Dust the top generously with additional confectioners' sugar.

Allow the marshmallows to set uncovered at room temperature for 4-6 hours or overnight until completely firm to the touch.

Turn the marshmallow slab out onto a work surface dusted with confectioners' sugar. Cut into 1-inch squares using a sharp, oiled knife or pizza cutter, wiping the blade clean between cuts.

Toss the cut marshmallows in a bowl with additional confectioners' sugar to coat all sides evenly. Store in an airtight container at room temperature for up to 2 weeks.