Preheat oven to 350°F. Line a 12x16x1-inch (or similar size) baking sheet with parchment paper, leaving a 1-inch overhang over the ends.

Line graham crackers up on the parchment paper so that the sides are touching.  Make sure the entire bottom of the pan is covered - I break mine up near the edges to squeeze them in.

(10-12 sheets of graham crackers)

In a medium saucepan, melt the butter and brown sugar over medium heat, stirring constantly, until smooth and mixture comes just to a boil, about 5 minutes. Remove from heat.

(1 cup salted butter, 1 cup brown sugar)

Stir in vanilla and sea salt flakes and pour evenly over crackers. Bake 5 to 6 minutes, or until bubbly.

(1 teaspoon pure vanilla extract,1 teaspoon sea salt flakes*)

Remove pan from oven and immediately sprinkle mini marshmallows, chocolate bar pieces, and chocolate chips over the crackers.

(4 cups mini marshmallows, 4 Hershey chocolate bars, 1 cup milk chocolate chips or chopped milk chocolate)

Return pan to oven for another 3-5 minutes, or until marshmallows begin to soften and puff up.

Remove from oven.

If you'd like to brown the marshmallows a bit more, set oven to broil. Give your oven a couple of minutes to heat up to broil if it needs it. Return pan to oven and broil for 30-60 seconds, or however long it takes to get nice & golden - watch carefully!

Lift from pan; cut into bars and enjoy!