Opera Creams...

4 C. sugar
1/8 tsp. cream of tartar
2 Tbsp. white corn syrup
1 pint half and half
1 tsp. vanilla

Mix sugar and cream of tartar in large heavy saucepan. Add syrup vanilla and half and half.
Cook over high heat, watching closely to make sure the cream does not curdle.
If cream should curdle remove from heat and beat rapidly with beater.
Otherwise do not stir candy after boiling starts unless it begins to stick to the bottom of pan.
Cook until candy reaches 240 degrees on candy thermometer.

Moisten large flat platter with water; pour hot candy onto platter. Let cool completely.
When cool work up candy with broad knife or spatula on the platter until candy becomes stiff, rather hard, but creamy mass.
Cover candy on platter with clean damp cloth and allow to stand covered for 2 hours.
Cut off pieces of candy and work with your hands until candy is soft.
Pat pieces into the bottom of a greased 8-9 inch square pan.
Continue to pat pieces of candy into the bottom to form a thick 1 inch layer. Cut into squares.