Preheat the oven to 325°F. Line a large jelly roll pan (15x10) with parchment paper or foil (spray foil with non stick spray).
Line the bottom of the pan evenly with saltine crackers. You may need a break a few on the sides to fill in the gaps.
In a medium pot, combine the butter and sugar over medium-low heat. Stirring constantly, bring to a rolling boil and cook 3 minutes, or until bubbling and amber in color (about 280°F). Remove pan from heat and pour evenly over saltine crackers. Spread brown sugar mixture quickly with a spatula.
Bake 8 minutes (caramel should be bubbling). Remove pan from oven and sprinkle chocolate chips over the top. Allow to sit 5 minutes. Once melted, spread evenly with a spatula. Sprinkle M&M’s (or nuts) over the top and place in the freezer 15 minutes, or until hardened.
Let sit 15 minutes on the counter. Flip over onto a cutting board and remove the foil. Break into pieces.
