In a small mixing bowl combine the graham crackers crumbs, brown sugar and melted butter until you have a crumbly mixture.
Take a large spoonful of the graham cracker mixture into the mason jars and use clean fingers to press and mold into the bottom of each container. Set aside.
In a saucepan or pot, pour the heavy cream, milk, vanilla, and sugar together and mix
Turn on medium hot and bring to a boil, stirring every few minutes
While you bring that to a boil, take a separate bowl with the eggs and whisk them.
Temper about ¼ cup of the heated milk mixture into the eggs by slowly pouring the milk into the eggs while stirring constantly until completely combined and the egg mixture is warm throughout.
Bring the milk mixture back to a simmer on the stove.
Add the tempered egg mixture into the saucepan or pot and stir constantly
Continuously stir until the cream mixtures thickens a little and then remove from the heat.
Take a large bowl with the peanut butter cups and pour the thickened mixture on top of the chocolates
Let it sit for one minute to allow the chocolates to start melting
Whisk together to completely melt the peanut butter chocolate cups and to create a slightly thick and emulsified peanut butter filling
Fill the mason jars ¾ way full with the peanut butter filling by spooning it into each jar or using a piping bag filled with the peanut butter filling with the tip snipped
Let sit in the refrigerator for 1.5 to 2 hours or overnight
Fill each mason jar to the brim with spoonfuls of marshmallow creme. Add about 8 mini marshmallows on top of the creme Set into the air fryer for 3-5 minutes at 300 degrees F, using air fryer setting. Cook until the tops are highly browned.