Grease an 8x8 inch pan or line it with parchment paper.
In a microwave-safe bowl, combine butter, corn syrup, salt, granulated sugar, brown sugar, and sweetened condensed milk. Stir well.
5 tablespoons unsalted butter, ½ cup light corn syrup, ½ cup granulated sugar, ½ cup brown sugar, ½ cup sweetened condensed milk, ¼ teaspoon salt
Microwave on high for 6–7 minutes, stirring every 2 minutes, until bubbling and thick. Perform a soft ball test after 6 minutes; if it doesn't form a soft ball in cold water, microwave for another 30 seconds to 1 minute.
The soft ball test is when a small drop of hot caramel is placed into cold water, forming a pliable ball that flattens easily between your fingers, indicating the caramel is ready.
Once done, stir in vanilla bean paste and pour the caramel into the prepared pan, sprinkle with sea salt and let it cool for 2 hours until set.
2 tsp vanilla bean paste, sea salt
Cut into squares and enjoy! For best results, let the caramels sit out of the fridge for 5-10 minutes before cutting with a sharp, greased knife to avoid sticking.