Combine Ingredients: In a medium saucepan, combine 1 1/2 cups milk chocolate chips, 3 tablespoons milk, and 1 1/3 cups miniature marshmallows. Heat over medium-high, stirring continuously until the mixture is melted and smooth. This should take about 3-5 minutes. Be careful not to burn the chocolate!
Transfer to Baking Dish: Pour the melted chocolate and marshmallow mixture into a 9-inch pie dish. Use a spatula to smooth it out evenly across the dish.
Add More Marshmallows: Top the melted dip with the remaining 4 cups of miniature marshmallows, spreading them evenly over the surface.
Broil: Place the dip in the oven and broil for just a couple of minutes, or until the marshmallows are golden brown. Watch closely to prevent burning!
Serve: Remove from the oven and let it cool slightly before serving. Pair with graham crackers for dipping. Enjoy this sweet treat!