Preheat the oven to 400 degrees.

Cover a rimmed baking sheet with foil and lightly spray with cooking spray.

Arrange the saltines in a single layer on the bottom of the baking sheet. Set aside.

Heat the butter in a medium saucepan over medium heat until melted.

Whisk in the brown sugar. Stirring constantly, bring the mixture to a boil and cook for 2-3 minutes until it begins to thicken.

Pour the butter and brown sugar mixture over the crackers. Using a spatula, gently spread the sauce until every corner of the crackers are covered.

Bake for five minutes until the sugar sauce is bubbly. Remove from the oven and allow the crackers to cool for about five minutes.

In the meantime, place the chocolate chips in a microwave save bowl. Heat for 30 seconds, stir, then continue to heat and stir at 30 second intervals until the chocolate chips are melted.

Pour the melted chocolate chips over the crackers. Using a spatula, gently spread the chocolate over the surface until every corner of the crackers are covered.

While the chocolate is still warm, sprinkle the top with the chopped pecans. Allow the toffee to cool to room temperature, then place it in the fridge to set overnight.

After the toffee has chilled, break it into smaller pieces.