Step 1

In the bowl of an electric mixer, sprinkle gelatin over 1/3 cup cold water. Allow gelatin to soften, about 5 minutes.

Step 2

In a small saucepan, combine 1/4 cup water and sugar, and stir over medium-high heat until sugar is dissolved. Stop stirring, and place a candy thermometer into sugar water; wipe sides of pan with a wet brush if sugar crystals have splattered up. Boil sugar until temperature reaches the soft-ball stage (238 degrees). Remove syrup from heat; add to softened gelatin. Using the whisk attachment of an electric mixer, hand-stir the mixture a few minutes to cool; place bowl on the mixer stand. Beat on medium high with the whisk attachment until soft peaks form and the marshmallow mixture holds shape, 8 to 10 minutes.

Step 3

Transfer marshmallow mixture to a large (14-inch) pastry bag fitted with a 1/2 inch (No. 11 Ateco) tip, and use immediately.