Preheat your oven to 350 degrees F. Line a baking sheet with parchment paper (or foil).
Arrange the graham crackers in a single layer over the bottom of the baking sheet. You may need to break some crackers into smaller pieces to fill gaps along the sides and corners. Set aside.
Place a medium saucepan over medium heat. Add the butter and brown sugar and stir until everything has melted together. Bring to a boil, stirring constantly. Once boiling cook for 1 minute while stirring.
Immediately stir the pecans into the praline mixture. Pour evenly over the graham crackers. (It will not fully cover them right now, that's okay.)
Bake for 10 minutes until bubbling.
Carefully remove the baking sheet from the oven and immediately sprinkle the toffee bits all over the top. Use a rubber spatula to gently press the toffee into the praline mixture. (DO NOT use your hands. The caramel is very hot.)
All to rest on the counter in the pan until room temperature. Once cooled, break into pieces or cut into pieces with a knife. (It's easiest to break up the candy after resting overnight.) Store in an airtight container for up to 1 week or freeze for up to 3 months.
Notes
Nutritional information will vary based on the number and size of the pieces you bream the praline sheet into.
Depending on the size of your baking sheet, you may need more or fewer graham crackers to cover the bottom of the pan completely.
If you want to substitute unsalted butter, be sure to stir in 1/4 teaspoon of salt into the butter and brown sugar mixture.
Light brown sugar can be used instead of dark brown sugar.
You can omit the pecans if desired. If you want to leave off the toffee bits, but keep the pecans, add the pecans on top instead of stirring them into the praline mixture.