Preheat the oven to 350°F (180°C) and line the mini muffin tin with 24 paper liners.
Place the whole graham crackers into a small resealable plastic bag. Close the bag tightly then use the bottom of a measuring cup or a small rolling pin to crush the graham crackers into crumbs.
Place the butter in a medium microwave-safe bowl then heat it in the microwave for 30 to 45 seconds until melted. Add the graham cracker crumbs to the bowl with the butter then carefully stir to combine them. It should look like wet sand. Scoop 1 teaspoon of the buttered graham cracker crumbs into the bottom of each muffin cup. You should still have some of the crumb mixture left to use for the top of the brownies. Use the back of the spoon to press the crumbs into the bottom of the cup to pack them down.
In a large bowl, stir together the egg, almond butter, applesauce, brown sugar, and vanilla. Add the baking soda, salt, cocoa powder, flour, and chocolate chips then stir to combine all the ingredients.
Using a tablespoon measuring spoon, scoop the brownie batter on top of each of the graham cracker crusts you already made.
Press 2 or 3 mini marshmallows into the top of each brownie then sprinkle with a pinch of the remaining graham cracker crumbs.
Using oven mitts, carefully place the muffin tin onto the center rack of your oven. Set a timer for 10 minutes and bake until the marshmallows are golden brown. If the marshmallows aren’t browned and the brownie batter still looks wet, set a timer for 2 more minutes and continue to bake.
Carefully use oven mitts or have a grown-up help you remove the pan from the oven. Allow the brownies to cool in the pan for 15 minutes before removing them from the muffin tin.
