Line a 15x10-inch jellyroll pan with nonstick foil.
Arrange whole graham crackers to fit the bottom of the pan in a single layer, breaking up the last few to fit the space.
Melt 8 ounces butter in a medium saucepan over medium heat.
Add ¼ cup brown sugar and ¼ cup white sugar.
Stir to combine.
Bring mixture to a boil.
Reduce heat and let the mixture gently bubble for 4 minutes.
Remove from heat.
Carefully pour sugar/butter mixture evenly over the graham cracker layer.
Spread to cover.
Bake for 10 minutes.
When done, remove from oven and let rest until bubbling subsides.
Sprinkle 2 cups semisweet chocolate chips evenly over the top.
Wait about 2 minutes for chocolate to melt, then use a spatula to gently spread chocolate chips into an even layer on top of the toffee graham crackers.
Cool to room temperature, then refrigerate for 2 hours.
Peel foil from chilled bark.
Crack into 2-inch irregular pieces.
Recipe by Amish 365 at https://www.amish365.com/?p=21055