Step 1: Preheat the oven to 325F. Line a baking sheet with parchment paper and line the baking sheet with the graham crackers until you have an even layer.
Step 2: In a medium pot, combine the butter and sugar over medium-low heat. Stirring constantly, bring to a rolling boil and heat for approximately 4 minutes, until the caramel is bubbling and thickens in texture.
Step 3: Remove the pot from heat and pour the caramel over the graham crackers. Spread the mixture with a knife or spoon, then bake for 7 minutes.
Step 4: Remove the baking sheet from the oven and place the chocolate on top. Return the baking sheet back in the oven for about 1 minute, to allow the chocolate to melt.
Step 5: Using a knife or spoon, spread the melted chocolate evenly. Then sprinkle sea salt on top. Place the baking sheet in the freezer for about 25-30 minutes.
Step 6: Remove the pan from the freezer and let it rest for a few minutes. Then break, or cut the crack into pieces.