Boil the water, sugar and 2/3 cup corn syrup to 230 degrees F. Bloom the gelatin in 4 tablespoons of water. Place the 3/4 cup corn syrup, bloomed gelatin and lemon juice in the mixing bowl of your stand mixer. Add the hot sugar syrup to the bowl and whip until light and fluffy, about 5 minutes. If you want to flavor and/or color the marshmallows, divide the mixture into 3 bowls and add the flavored oil and food color.
Lightly spray vegetable cooking spray onto a parchment paper lined baking sheet. You will need a pan for each flavor and/or color that you make. Spread the marshmallow mixture onto the baking sheet so the top is smooth. Mix equal amounts of cornstarch and powdered sugar together and dust the top of the marshmallows. Let the marshmallows dry overnight, then dust again with cornstarch and powdered sugar.
Spray a sharp knife with cooking spray, then cut the marshmallows into long strips. Weave or braid 3 strips of different colors. Serve.