Homemade Caramel Sauce

2 cups sugar
1 cup light corn syrup
1 cube butter
1 ¼ cup heavy cream, divided
1 teaspoon vanilla

In a heavy saucepan, mix together sugar, corn syrup and butter and bring to a boil. Cook to 237 degrees on a candy thermometer. Slowly add ¾ cup of the cream and bring mixture back to 237 degrees. Then add the remaining ½ cup cream and vanilla. Stir just until incorporated then take off heat and let cool slightly and thicken up a bit before drizzling over ice cream.