Lightly spray or coat your loaf pan with oil.
Cut a piece of parchment paper (wax paper will NOT work) to fit inside a loaf pan and go up the sides a couple of inches. Then lightly spray the parchment paper with oil and set aside.
Cut butter into pieces and add to heavy cream. Melt together in the microwave for approximately 1 min. or until butter is completely melted. Keep close, but set aside.
In a saucepan on low-med heat, gently add water, sugar and corn syrup. Bring to boil. Add a candy thermometer (try not to let thermometer touch bottom of the pan).
Now have your melted butter/cream ready and watch candy thermometer until it reaches exactly 320°. Heat should be on medium.
As soon as it reaches 320°, carefully add a little bit of your butter/cream mixture. It will bubble up quickly, stir with the bottom of a candy thermometer and pour in a little more mixture, stir and continue the process until all of the butter/ cream mixtures are combined.
Now replace your candy thermometer and watch for 240° (softball stage). It may take a little while to get back up there (5-10 min.), but don’t get distracted!
As soon as 240° temperature is reached, pour the mixture into your loaf pan lined with parchment paper.
Let sit for about 10 minutes and then sprinkle with the desired amount of course sea salt.
Let cool for a few more hours before unmolding and cutting (may also place in the fridge for a bit). Use a large sharp knife to get nice squares or rectangles.