Line an 8x8-inch baking pan with parchment paper. Lightly butter the parchment, set aside.
In a large microwave-safe glass bowl, add butter. Place in microwave and melt, about 1 minute on HIGH.
Add sugars, corn syrup, condensed milk and salt to the mixing bowl, whisk to combine.
Place in microwave and cook mixture on HIGH for 6-8 minutes, removing to stir every 2 minutes (the temperature of the finished caramel should be right around 240 degrees).
Remove the bowl from microwave and whisk in vanilla and vanilla bean, if desired.
Pour into the prepared baking pan. Sprinkle top with sea salt.
Place pan in refrigerator to allow caramels to set, about 30 minutes. Cut into long strips, then into thirds, or cut into squares. Wrap caramels in wax paper.