Grease a 9"x13" glass pan. Sprinkle 2 tablespoon confectioners' sugar in pan and shake around until sugar coats the bottom and sides. Set aside.
Mix ½ cup cold water and unflavored gelatin in bowl of a stand mixer. Set aside.
In a three-quart saucepan set over low heat, add sugar, corn syrup, salt, and remaining ½ cup water. Whisk until sugar has dissolved and all ingredients are mixed. Insert candy thermometer and let mixture slowly cook and bubble until temperature reaches just under 240°F.
Remove sugar/corn syrup mixture from heat and slowly pour into the gelatin mixture.
On high speed, mix on high speed for 2-3 minutes. Add vanilla extract, raspberry syrup, and 10 drops of the red food coloring. Mix on high for another 6-8 minutes, or until mixture about triples in volume and is a light pink in color and resembles the consistency of marshmallow creme.
Pour marshmallow mixture into prepared pan and flatten the top with damp hands. Drop 10 or so drops of red food coloring on top and drag a knife through to swirl color. Let marshmallow pan sit for eight hours (or overnight).
To serve, grease a sharp knife and cut marshmallow into squares of your desired size. Press bottoms and sides of marshmallows into bowl with remaining confectioners' sugar. Repeat for all marshmallows.
Nutritional information is provided as an estimate. As it can vary due to many factors (brands used, quantities, etc.), we cannot guarantee its accuracy.