1/2 cup butter
1/2 cup light corn syrup
1/2 cup light brown sugar
1/2 cup white sugar
1/2 cup sweetened condensed milk
1 teaspoon vanilla
Butter an 8-inch square pan, or for thicker caramels, a 9×5 inch loaf pan. If you like, you can then line the buttered pan with foil and butter the foil.
Melt butter in a large microwaveable bowl (microwave for about 1 minute).
Stir in the corn syrup, both sugars and sweetened condensed milk. Continue stirring until most of the sugar is dissolved.
Microwave on high for 3 minutes and 5 to 15 seconds. ( I recommend starting with the shorter time of 3 minutes 5 seconds, since I’d rather have my caramels too soft than too hard). Remove from microwave and stir and scrape down the sides of the bowl.
Return to microwave and cook on high for another 3 minutes and 5 to 15 seconds. Stir in the vanilla. Pour immediately into the buttered dish.
Allow to sit for several hours until cooled and set. Cut into squares and wrap in waxed paper.