1 cup dark Karo syrup
1 cup real butter
1 (14 ounce) can Eagle Brand Sweetened Condensed Milk (NOT evaporated)
1 teaspoon vanilla
In a medium saucepan on medium high heat; mix the sugar, syrup, and butter. Stir to mix well and continue stirring until the mixture comes to a ploppy boil. Continue to boil in this manner for 5 to 7 minutes. DO NOT STIR!
Take off the heat and add the condensed milk. Stir to mix well, put back on the stove and bring back to a slow boil, stirring constantly. Continue to stir constantly at this slow boil for 12 to 15 minutes, the mixture will began to thicken.
Remove from the heat and add the vanilla. Mix well. Pour into a lightly buttered 8" x 8" pan. Cool overnight at room temperature, the mixture will harden. Cut into squares and wrap each piece in wax paper.