01 -
Warm up your oven to 350°F. Coat a 9x13 pan with non-stick spray or line it with parchment paper to make it easy to remove the treats later.
02 -
Combine the crushed graham crackers with the melted butter in a bowl until it's evenly mixed. Press this mixture into the pan's bottom in a tight, flat layer.
03 -
Drizzle the sweetened condensed milk all across the top of the crust. Make sure it's completely covered.
04 -
Scatter half (1 cup) of the marshmallows, then add the chocolate chunks and graham cracker bits. Spread everything evenly on top of the milk layer.
05 -
Pop the dish into the oven and bake for about 15 minutes until you see bubbling edges and the marshmallows starting to puff up slightly.
06 -
Take the dish out of the oven. Sprinkle on the remaining marshmallows, covering any bare spots.
07 -
Bake again for 10-15 minutes. Remove once the top marshmallows are golden and toasted, and the edges look set.
08 -
Right after removing the dish from the oven, lay the chocolate bar pieces gently on top of the hot marshmallows so they soften slightly.
09 -
Let the bars cool on a rack for around 15 minutes before cutting into them. For neat slices, wait until they’re completely cooled—but they'll still taste great a little gooey.