Line a rimmed half sheet pan (13 x 18-inches) with parchment paper and oil the paper.

In the bowl of an electric mixer, combine the gelatin with 1 cup water and let sit.

Combine granulated sugar, corn syrup, 1¼ cups water, and salt in a heavy saucepan. Bring to a boil over high heat and continue to boil until the syrup reaches a temperature of 240°F on a candy thermometer.

Using the whish attachment for the mixer, beat the gelatin at high speed while carefully pouring in the syrup. Continue to beat for 15 minutes. The mixture will be white and fluffy and stiff. Add the vanilla paste and beat until fully incorporated.

Using an oiled spatula, scrape the mixture into the prepared pan and smooth the top. Let sit at room temperature 10–12 hours.

Lift the marshmallow out of the pan using the parchment paper and cut into shapes with well oiled cookie cutters.

Pour the sanding sugars into small plates and dip the marshmallows into the sugar, coating well.