Preheat oven to 350*

Use a cookie sheet or jelly roll with an edge. *If you are using a cookie sheet instead it will not be big enough for all 40 crackers but it will work as long as it has an edge.
Cover pan with heavy duty tin foil
Spray with Pam
Cover with 40 soda crackers, salt side up

On stove top, combine in sauce pan:
1 cup butter (not margarine)
1 cup brown sugar
Bring to a boil and continue to boil for 3 minutes

Remove from heat and spread on top of crackers
Bake in oven for 5 minutes

Remove from oven

Sprinkle crackers with:
1 cup milk chocolate chips
1 cup butterscotch chips
Spread with spatula until the chips are melted

Sprinkle with chopped walnuts (optional - I don't)
Refrigerate for a few hours
As soon as it has cooled sufficiently, break into pieces