Line cookie sheet with aluminum foil or parchment paper and spray with nonstick spray. Preheat the oven to 400 degrees.
Line the cookie sheet with crackers in a single layer.
Add the brown sugar and butter to a medium saucepan and bring to a boil on medium-high heat. Stir occasionally.
Boil for 3 minutes.
Gently pour the toffee mixture over the crackers. Spread to the edges with a rubber spatula if necessary.
Place in a 400-degree oven for 5 minutes.
Take out of the oven and sprinkle chocolate chips on top.
Let the chips sit for a few minutes to get melty. (If your chips won’t spread well because they’re not melted enough, pop the tray back into the oven for a minute, then remove the pan to finish the spreading).
Spread the chocolate to the edges.
Top with sprinkles, pecans, or whatever you'd like.
Put in the refrigerator or freezer until hardened. (You can leave the candy out on the counter at room temperature to harden, but it will take longer).
Break into pieces.