You will want to have everything prepped and ready to go ahead of time. Once the marshmallows are ready to pour you need to work fast as everything starts to set up quick. Make sure to have whisk attachment ready for your stand mixer or hand mixer as well.
Line a 9x13 pan with parchment paper. Set aside for later.
Soak the gelatin in 1/2 cup of cold water in the bowl of a stand mixer or large bowl with your whisk attachment ready.
In a large saucepan dissolve the sugar in 1 1/2 C of water over low heat, stirring constantly.
Raise the temperature and bring to a boil - once it comes to a boil don't stir anymore.
Boil steadily until the mixture hits 240. It should take 7-15 mins.
Remove from the heat and pour into bowl with gelatin. Begin whisking and add in your vanilla extract, mint extract, and green food coloring (if using), start with a little bit of food coloring adding in more if you desire a more vibrant color.
Continue whisking until mixture has tripled in size, the bowl is cool to the touch, and when the whisk is removed the drizzle holds its shape in the bowl. Fold in the mini chocolate chips at this point.
Pour mixture into your prepared pan and let set completely - about 2 hours.
Remove marshmallows from the pan and sprinkle with additional powdered sugar. This helps your knife from sticking too much when cutting.
Cut marshmallows into desired size with a sharp knife. Dipping each marshmallow in powdered sugar to prevent them all from sticking to each other.
Store in an air tight container for up to 2 weeks.