Line a 9 x 13-inch baking pan with foil or parchment lined foil. Butter any sides of the dish that are not covered in the liner.
Using a medium to large saucepan (I used an 8 quart because hot bubbling sugar scares me), begin to melt butter over medium high heat. Whisk continually as butter melts and bubbles, scraping any brown bits off the bottom of the pan. When butter has successfully browned, you will have a wonderful caramel nutty aroma. Remove from heat.
Combine the water, sugar, vanilla beans with scraped seeds, condensed milk, corn syrup, and browned butter in the saucepan. Bring to a boil, stirring constantly with a heat-resistant rubber spatula. Continue stirring while cooking until the batch reaches 245ºF. You may need to use a heat protective glove over your hand while stirring.
The instant the caramel reaches 245ºF, immediately pour into the prepared pan and remove the vanilla bean pods using a fork. If you do this too early, the caramel won't set. If you take the temperature above the setpoint, you risk having caramel that's hard as a rock as opposed to chewy.
As soon as you've poured the caramel, sprinkle the salt flakes over the surface. Allow to cool completely to room temperature, at least 2 hours. Remove the sheet of caramels from the pan. Cut into the desired size pieces using a sharp chef's knife. For easy wrapping, caramels may be chilled before handling. Wrap in pieces of wax paper for individual treats. Store in airtight container at room temperature.