1- Prepare your pan by greasing the bottom and sides of a 9-inch baking pan with vegetable shortening or softened butter. Lightly dust with powdered sugar to create a non-stick layer that will help when removing the marshmallows later.

2- Bloom the gelatin by pouring 1/3 cup of cold water into the bowl of your stand mixer. Sprinkle the gelatin evenly over the water and let it sit without stirring for about 5 minutes. This allows the gelatin to absorb the water and soften, preparing it to create the marshmallow structure.

3- While the gelatin blooms, make the sugar syrup. In a saucepan, combine the remaining 1/3 cup water, granulated sugar, light corn syrup, and salt. Cook over medium heat, stirring until the sugar dissolves. Then, bring to a boil without stirring, occasionally brushing down any sugar crystals that form on the sides of the pan with a pastry brush dipped in water. Continue cooking until the mixture reaches 240 degrees Fahrenheit on a candy thermometer, about 10 minutes.

4- Once the syrup reaches temperature, carefully pour it into the gelatin mixture in the stand mixer. With the mixer on low speed, slowly pour the hot syrup down the side of the bowl to avoid splashing. After all the syrup is added, increase the mixer speed to medium. For additional guidance on this technique, check out expert marshmallow-making techniques from professional bakers.

5- Whip the mixture for 10 to 11 minutes until it becomes white, thick, and has increased significantly in volume. The mixture should be fluffy but still slightly warm to the touch when ready.

6- Add flavoring by beating in the vanilla extract and vanilla bean paste during the last minute of whipping. Mix just until they are fully incorporated and evenly distributed throughout the mixture.

7- Quickly transfer the marshmallow mixture to the prepared pan, spreading it evenly with a greased spatula. Work swiftly as the marshmallow begins to set. Lightly dust the top with powdered sugar.

8- Cover the pan with a clean kitchen towel to protect from dust while allowing air circulation. Let the marshmallows rest at room temperature for at least 6 hours or overnight until completely set.

9- To cut, turn the marshmallow out onto a cutting board generously dusted with powdered sugar. Grease a sharp knife with vegetable shortening or butter, then cut the marshmallow slab into strips and then squares (the recipe suggests 5 strips, then cutting each into 5 pieces for 25 large marshmallows). Grease the knife between cuts and dust the cut edges with powdered sugar to prevent sticking.