Melt the butter and mix it with the Pie Crust Mix. Press into a 9" pie pan. Place in the fridge for at least one hour.
Add the Jello powder, cornstarch and milk to a stand mixer bowl and whisk until smooth.
Pour into the chilled crust, then cover. Place in the fridge for at least one hour or until set.
Place the marshmallows in a bowl and microwave in short bursts until melted. Spread the marshmallow over the top of the pie.
6g net carbs per servingNote: The marshmallows contain sugar alcohols which are not included in the above carb count. If you include sugar alcohols as carbohydrates in your diet, the total will be nearer 12.4g net carbs per serving.