My mom would make this toffee as a Christmas candy. It doesn't require a candy thermometer, which makes it easier on the candy scale.
37 saltine crackers
1 cup butter
3/4 cup sugar
12 oz. semi-sweet chocolate chips
1 to 2 oz. white chocolate chips
Preheat oven to 350ºF. Place crackers in a single layer on a foil-lined 15 x 10 x 1 baking pan. In a pan, bring butter and sugar to a boil. Reduce heat, and simmer uncovered 5 to 6 minutes or until mixture is thickened and sugar is completely dissolved. Spread mixture over crackers, and bake for 7 to 8 minutes until bubbly.
Sprinkle with chocolate chips, and put back in the oven for 3 to 5 minutes or until chips begin to melt. Spreak the chocolate evenly over the cracker mixture. Melt the white chocolate in the microwave, and drizzle over the toffee.
Chill until set, and then break into pieces. Store in refrigerator. Makes about 1 3/4 lbs.