Tahitian Vanilla Bean Marshmallows

About 40 marshmallows

Flavorless vegetable oil for the pan

3 3⁄4 teaspoons unflavored gelatin

3 tablespoons water

2 cups granulated cane sugar, divided into halves 1 1⁄2 cups light corn syrup

4 extra-large egg whites, at room temperature 1 Tahitian vanilla bean, split horizontally

About 3 cups powdered cane sugar for finishing

Line the bottom of an 8-by-12-inch sheet pan with parchment paper and lightly coat the paper and the pan sides with flavorless vegetable oil. Put the gelatin in a small bowl. Add the water and stir. Set aside to soften.

Combine 1 cup of the sugar with the corn syrup in a large, heavy-bottomed pot. Use an unlined copper pot if you have one. Place over medium heat and cook, stirring occasionally with a wooden spoon, until the sugar melts. Then continue to cook, without stirring, until the mixture reaches 230 F on a candy thermometer. If any crystals form on the sides of the pan and the mixture heats, wash them down with a wet pastry brush.

Meanwhile, put the egg whites in the bowl of a stand mixer fitted with the whip attachment. Scrape the seeds from the vanilla bean into the bowl.

When the sugar syrup reaches 240 F, start to beat the egg whites on medium speed. When the whites form very soft peaks, add the remaining 1 cup sugar and continue beating.

When the sugar syrup reaches 250 F, remove it from the heat and stir in the softened gelatin. The syrup will foam up and triple in volume. Switch the mixer to high speed and slowly pour the syrup into the beaten egg whites, aiming for the side of the bowl. The whites will almost double in volume. Reduce the speed to medium-high and beat until the whites (not the outside of the bowl) are lukewarm to the touch, about 114 F, about 15 minutes.

Scrape the marshmallow mixture into the prepared pan and, using a small offset spatula, spread it evenly to the sides. Let cool completely at room temperature.

To cut the marshmallows, sift about 1⁄2 cup of the powdered sugar onto a work surface in a rectangle the size of a sheet pan. Sift another 2 cups powdered sugar into a large bowl. Run a thin-bladed knife around the edge of the pan to loosen the marshmallow. Invert the pan onto the sugared surface to unmold, then lift off the pan and peel off the parchment paper. Sift about 1⁄2 cup powdered sugar evenly over the top. Using a ruler to guide you and a lightly oiled sharp knife, cut the marshmallow sheet into 11⁄2-inch squares. It is easier if you use a pressing motion, rather than pull the knife. After cutting, toss the marshmallows, a few at a time, in the bowl of powdered sugar, coating them lightly.