01 - Line a large baking sheet with parchment paper or a silicone baking mat. Arrange graham cracker pieces in a single layer with edges touching.
02 - In a medium saucepan over medium heat, melt the butter. Add brown sugar, maple syrup, vanilla extract, and salt. Bring to a gentle boil, stirring constantly, and simmer for 2-3 minutes until thickened and glossy.
03 - Pour the hot caramel mixture evenly over the graham cracker base, spreading carefully with a spatula to cover all pieces.
04 - Sprinkle toasted chopped pecans evenly over the caramel layer. Bake in a preheated oven at 350°F for 8-10 minutes until the caramel bubbles.
05 - Remove from the oven and immediately scatter chocolate chips evenly across the top. Let sit for 3-4 minutes, then spread the melted chocolate into a smooth, even layer using an offset spatula.
06 - Optionally sprinkle with flaky sea salt. Allow to cool completely at room temperature, or refrigerate for faster setting.
07 - Once fully set, break the bark into irregular pieces. Store in an airtight container at room temperature for up to 1 week.