Preheat your oven to 350°F and line a baking sheet with parchment paper.
Arrange the graham crackers in a single layer, side by side.
In a saucepan, melt the butter and brown sugar together. Bring it to a gentle boil, stirring constantly. Let it bubble for 2 minutes.
Pour the butter-sugar mixture evenly over the graham crackers. Spread gently with a spatula.
Bake for 7-8 minutes until the mixture is bubbly.
Remove from oven and immediately sprinkle chocolate chips over the top. Let them sit for 2 minutes to melt.
Spread the melted chocolate evenly with a spatula. Top with chopped pecans if using.
Let cool completely, then break into pieces and enjoy!