Line an 8x8 pan with parchment paper and generously spray with non-stick cooking spray.

In the bowl of a stand mixer, pour in 1/2 cup cold water and sprinkle the gelatin evenly over the top. Let it sit (bloom) for 10 minutes.

In a medium saucepan, combine the granulated sugar, corn syrup, salt, and remaining 1/2 cup cold water. Place over medium-high heat.

Clip a candy thermometer to the pan and boil the mixture without stirring until it reaches exactly 240°F (115°C). Remove from heat immediately.

Turn the stand mixer on low speed and carefully pour the hot syrup down the side of the bowl into the bloomed gelatin.

Gradually increase the speed to high and whip for 10-12 minutes until the mixture is thick, white, and fluffy. Add the cotton candy extract during the last minute.

Quickly remove 1/3 of the white fluff to a separate bowl and fold in the blue food coloring until vibrant.

Spread half of the remaining white fluff into the prepared pan. Layer the blue fluff in the center, and cover completely with the rest of the white fluff.

Let the marshmallows set at room temperature for 6-8 hours or overnight.

Remove the block from the pan. Using a heavily greased knife, cut into cubes. Roll each sticky cube in the pink sanding sugar until fully coated.