Step 1

Spray an 8-inch square pan with cooking spray then line with parchment paper so that two two ends extended over two edges of the pan. Spray the parchment with cooking spray also. Set aside. Prepare a small bowl of water with a few ice cubes and set aside.

Step 2

Place butter in a large microwave-safe bowl* and cover with a paper towel. Cook on high power for one minute. Butter should be mostly melted. Add corn syrup, sugars, sweetened condensed milk and salt and whisk well to combine.

Step 3

Cook on high power for 7 minutes. Remove and give mixture a quick stir then check for doneness by placing a bit (a small spoonful) of the caramel into the prepared bowl of ice water. It should form a soft, pliable ball. If it needs a little more time (it doesn’t form a soft ball), return to microwave and heat in 15-20 second increments, till soft ball stage is reached. Mine was done at right around 7 1/2 minutes but time will will vary a bit based on the wattage of your microwave. You can also check with an instant thermometer which should register 240-242˚F (240˚ will yield a softer caramel and 242˚ firmer. Carefully remove bowl from microwave (it will be hot - that’s why I love the Pyrex with the handle). Add vanilla bean paste or vanilla extract and stir with a heat resistant spatula until foaming subsides.

Step 4

Pour mixture into prepared baking dish. Allow to cool for 10 minutes then sprinkle top lightly with flaky sea salt (I like Maldon) If you sprinkle with sea salt right away, the salt will melt right into the caramels rather than sitting on the top. Allow to cool for 3-4 hours or refrigerate until completely cool and set. Cut into rectangular pieces (I cut into rows about 1/2-inch wide and then cut each row into three equal pieces). A pizza cutter works wonderful for cutting caramels. Wrap in rectangles of wax paper, parchment or pre-cut candy wrappers and twist on both ends.