Preheat oven to 400 degrees (F)
Line a baking sheet with foil.
Lay the saltine crackers on the baking sheet, arranging so no space remains between the crackers. It's okay to break the crackers into pieces to fit as needed.
Melt the butter in a medium-sized saucepan over medium heat then add the sugar and stir until it dissolves. Bring to a boil then reduce the heat to medium-low and boil for 4 minutes.
Immediately pour over the saltine crackers and using a spatula, make sure all the crackers are covered with the mixture.
Bake for 7 - 9 minutes, or until bubbly. Remove from the oven and sprinkle the chocolate chips over the top and return to the oven for 1 minute.
Remove from the oven and using a spatula, spread the chocolate over the tops of the crackers. Make sure the chocolate covers the entire surface.
Sprinkle the toffee pieces over the top of the melted chocolate.
Cool to room temperature for 30 minutes then place in the refrigerator for 30 - 60 minutes, or until the chocolate is firm.
Remove the Christmas Crack from the pan and break into pieces. Store in an airtight container for up to two weeks.