01 - Set oven to 175°C (350°F) to preheat.
02 - Mix brownie ingredients according to package instructions, combining eggs, oil, and water with mix until smooth.
03 - Position mini graham cracker pie crusts evenly on a rimmed baking sheet.
04 - Spoon brownie batter into each pie crust, filling no more than two-thirds full to allow for rise.
05 - Bake in the center of the oven for 20 to 25 minutes, or until a toothpick inserted comes out with moist crumbs.
06 - Remove pies from oven. Sprinkle mini marshmallows and chocolate chips evenly over warm brownie bases.
07 - Return pies to oven and bake 3 to 5 additional minutes, or until marshmallows are puffed and lightly golden.
08 - Allow pies to cool for 10 to 15 minutes. Enjoy while warm or at room temperature.