Preheat the oven to 200 degrees C. Grease a 25x38cm cake tin.
Arrange cinnamon biscuits with sides touching in a single layer to cover the bottom of the tin.
Sprinkle the walnuts evenly over the crackers. In a small saucepan over medium heat combine the brown sugar, butter and cinnamon. Cook stirring constantly until the mixture begins to boil. Continue to boil the syrup for 3 minutes without stirring. Remove from heat and pour over biscuits.
Bake for 8 to 10 minutes in the preheated oven until bubbly and slightly darker around the edges.
Cool completely in the tin.
Break into pieces and store in an airtight container at room temperature.