Use a large microwave safe mixing bowl (a 2-quart Pyrex measuring bowl with a spout is perfect to prevent boiling over that is both a burn hazard and a big clean-up mess)

1/2 cup butter
1/2 cup Karo syrup
1/2 cup light brown sugar
1/2 cup granulated sugar
1/2 cup sweetened condensed milk (not evaporated milk)
1/2 teaspoon vanilla
1/2 cup chopped nuts (optional)

Butter an 8 x 8″ dish. (I had no problem removing the caramel from the dish but if you are concerned, line the pan with foil, extending foil over edges. Butter the foil.)

Melt butter in large microwave bowl in the microwave. Remove bowl from microwave, add the Karo syrup, light brown sugar, granulated sugar and the sweetened condensed milk. Stir. Microwave on high 3 1/2 minutes. Carefully remove from microwave, stir. Return to microwave for 3 1/2 more minutes. Remove from the microwave; add the vanilla and chopped nuts (if using, I didn’t). Stir gently until only a few air bubbles remain.

Pour into prepared pan and set aside to cool completely. Cut into squares and wrap individually using squares of waxed paper. Wrapping isn’t necessary, is time consuming but does make the caramels look special.

RECIPE NOTE:  I made a second batch using the other half a can of sweetened milk.  I thought about just doubling the recipe but was concerned that the cooking time would need to be changed to insure firm caramels.  The recipe is so quick and easy, making a second batch is not problem.

Here is a similar recipe for Chewy Caramel from Allrecipes cooked on the stove using a candy thermometer. Diana’s recipe is so easy and so good, I see no reason to make caramels any other way.