adapted from: Sweet
2 sticks (1 cup) unsalted butter
2 c. sugar
1 1/4 c. light corn syrup
1 (14 oz.) can sweetened condensed milk
1/4 c. unsweetened cocoa powder
Sea salt, for sprinkling
Line a 9x13-inch baking dish with parchment paper and spray with cooking spray. Melt the butter in a large saucepan over medium heat; add the sugar, corn syrup, sweetened condensed milk and cocoa powder. Bring to a boil and cook, stirring occasionally, until a candy thermometer registers 248 degrees, about 15 minutes. Carefully pour the hot caramel mixture into the prepared pan, sprinkle with Sea salt and let cool. Cut into 1-inch squares.
For High Altitude: Subtract 1 degree from the final temperature for every 500 feet you are above Sea level. I am at around 4600 feet above Sea level, so I subtracted 9 degrees. I took my caramel off the heat once it reached 239 degrees, but it still took right around 15 minutes.