For the bloom:
1/2 cup plus 2 tablespoons cold water
1 1/2 tablespoons vanilla extract
3 tablespoons unflavored gelatin
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For the base:
3/4 cup water
1 1/4 cups Marshmallow Syrup
Pinch of salt
1 1/2 cups granulated cane sugar
1 1/2 cups confectioners’ sugar
1/2 cup cornstarch
Makes 36 servings.
Spray the bottom and sides of a 9-by-13-inch or 11-by-15-by-1-inch pan or another mold you will be using for the batter with a nonstick spray coating, and wipe it lightly with a paper towel, leaving only a thin film of oil.
For the bloom: Measure the cold water into a measuring cup and add vanilla. Place the gelatin into a small bowl and pour the water and vanilla over it, stirring with a whisk or fork until there are no lumps. Set the bowl near the stove.
For the base: Place the water, syrup, salt and sugar, in that order, into a 4-quart pan. Bring the mixture to a boil over medium-high heat. Then place a lid on the pan and boil it, covered, for 2 minutes. This step is essential in order to eliminate sugar crystals on the side of the pan that may cause the marshmallows to crystallize.
Remove the lid, insert a candy thermometer, and continue boiling until the thermometer reaches 250 degrees. Do not stir the mixture once the lid has been removed. Remove the thermometer and gently stir in the bloomed gelatin.
Pour the batter into the bowl of an electric stand mixer. Beat it on high speed 10 to 12 minutes, using the wire whisk attachment. Cover the mixer with a clean kitchen towel for the first 3 to 4 minutes to avoid splattering hot liquid.
At first, the marshmallow batter will look very watery; as it beats, it will become thick, white and glossy and will increase in volume by two- to threefold. Remove the bowl from the mixer stand and spread the batter into the pan. Smooth the top with a spatula, or wet your hand and smooth the mixture with your palm. Let the pan sit at room temperature, uncovered, at least 4 hours or overnight.
For the coating: Sift the sugar and cornstarch together, or pulse in a food processor until there are no lumps. Store the coating indefinitely in an airtight container.
To cut: Prepare cutting surface by lightly sprinkling with coating mixture. Ease the marshmallows away from the sides of the pan and flip the pan over, gently releasing the slab onto the surface. Cut marshmallows with pizza cutter into desired shape. Toss the cut marshmallows with coating mix, shaking off any excess. Store in an airtight container for up to a week.
Coating variations: For gingerbread, add 1 1/2 teaspoons ginger, 1 teaspoon cinnamon and 3/4 teaspoon cloves to basic coating. For cocoa-ancho chile, add 1/2 cup unsweetened natural cocoa and 2 teaspoons ancho chile powder to basic coating. For cinnamon, add 2 to 3 teaspoons ground Vietnamese cinnamon to basic coating.
Nutritional information per marshmallow: 86 calories (none from fat), no fat, no cholesterol, 21 grams carbohydrates, trace protein, 4 milligrams sodium, trace dietary fiber.