Once you make homemade marshmallows, there's no turning back. These are fabulous, vanilla-flavored soft, fluffy, bouncy pillows that are not hard to make if you organize your ingredients and space beforehand. They can be stored for a month.
Put the first ½ cup cold water in the bowl of a stand mixer. Sprinkle 2 tablespoons unflavored gelatin powder on top and let it hydrate.
Line a baking pan with 2-inch sides with parchment paper and spray the entire surface with vegetable spray. Reserve.
In a medium saucepan, put 2 ¼ cups granulated sugar, ½ cup corn syrup (or glucose), and the remaining ¾ cup water.
Cook over medium heat until it dissolves, brushing the sides of the pan, just above the mixture, with a wet pastry brush so that sugar crystals don't form. Increase the heat to high, put the candy thermometer on the pan, and boil until it reaches 248ºF (120ºC), between the soft-ball and hard-ball stages.
Attach the bowl to the stand mixer with the whisk attachment and start beating the gelatin in the bowl.
Slowly, but constantly, pour the sugar syrup into the gelatin while beating at high speed. Try not to pour it directly over the whisk but between the side of the bowl and the whisk, that way the most syrup will reach the gelatin and not be stuck in the beaters or sides of the bowl.
Keep beating for some minutes until the consistency is fluffy, like a thick meringue. But don't let the bottom of the bowl cool completely, as that means the mixture is too stiff and the marshmallows will be tougher than we want.
Add 1 ½ teaspoons vanilla extract and stir to mix.
Immediately transfer the marshmallow mixture to the prepared pan, and smooth the top with an oiled or sprayed spatula.
Let dry at room temperature for 1 hour and sift 1 cup powdered sugar over the marshmallow mixture. Let dry for a few hours until it's no longer sticky and can be removed.
When ready, lift the parchment paper, and use an oiled or sprayed kitchen knife to cut it. You can also use an oiled pair of scissors. Dust each square completely with powdered sugar.
Store in an airtight container for up to a month in a dry, cool place.
Notes
Stand mixer: is highly recommended. Making them with an electric mixer can be done, but you'll have to manage to add the syrup in a thin stream while beating the gelatin mixture, and it can be a little challenging.Corn syrup or glucose? The latter is stickier, so I choose corn syrup whenever I can. Tip: lightly coat the measuring cup with spray or oil before measuring it. That way, it will slide out more easily.Candy thermometer: it's essential for this recipe as the syrup needs to reach a certain temperature, and it's hard to eyeball it. Use high heat when making the syrup; otherwise, it will take forever to get to the right temperature. It takes about 10 minutes anyway.Lining the pan: Use parchment paper and cooking spray to coat the sides of the paper and the spatula you'll use to spread the mixture.Cornstarch: Some old recipes call for sprinkling some with powdered sugar on top, but beware as the flavor is chalky and not good. I now use only powdered sugar. Humidity: I must add, as left in the comments, that attempting these on high-humidity days might be extra challenging. Storing marshmallows: Airtight container: like a mason jar or plastic container with a tight-fitting lid. Place them with wax paper between them and ensure they're not squeezed. They last for about a month. Plastic bag: use Ziploc-style bags. Make sure they're not overlapping so they're not squeezed. Room temperature: choose a cool, dry place, like the pantry. Refrigerator: you can store them in the fridge, but there's really no need. I find they don't keep as well.