Makes about 20 assorted holiday cookie cutter shaped marshmallows.
About 1 cup confectioners’ sugar
3 1/2 envelopes (2 tablespoons plus 2 1/2 teaspoons)
unflavored gelatin 1 cup cold water, divided 2 cups granulated sugar
1/2 cup light corn syrup
1/4 teaspoon salt
2 large egg whites
1 tablespoon vanilla
Oil bottom and sides of a 13- by 9- by 2-inch rectangular metal baking pan and dust bottom and sides with some confectioners’ sugar.
In bowl of a standing electric mixer or in a large bowl sprinkle gelatin over 1/2 cup cold cold water, and let stand to soften.
In a 3-quart heavy saucepan cook granulated sugar, corn syrup, second 1/2 cup of cold water, and salt over low heat, stirring with a wooden spoon, until sugar is dissolved. Increase heat to moderate and boil mixture, without stirring, until a candy or digital thermometer registers 240°F, about 12 minutes.
Remove pan from heat and pour sugar mixture over gelatin mixture, stirring until gelatin is dissolved.
With standing or a hand-held electric mixer beat mixture on high speed until white, thick, and nearly tripled in volume, about six minutes if using standing mixer or about 10 minutes if using hand-held mixer.
In separate medium bowl with cleaned beaters beat egg whites (or reconstituted powdered whites) until they just hold stiff peaks. Beat whites and vanilla (or your choice of flavoring) into sugar mixture until just combined. Pour mixture into baking pan and don’t fret if you don’t get it all out (learning from my mess of a first round). Sift 1/4 cup confectioners sugar evenly over top. Chill marshmallow, uncovered, until firm, at least three hours, and up to one day.
Run a thin knife around edges of pan and invert pan onto a large cutting board. Lifting up one corner of inverted pan, with fingers loosen marshmallow and ease onto cutting board. Coat a 1- or 2-inch holiday-shaped cookie cutter with oil or cooking spray to prevent it from sticking. Cut out as many individual marshmallows as possible; coat cutter with more spray as needed. Use marshmallows immediately or store in an airtight container at room temperature up to 1 week.