Start by lining a 8x8 square pan with parchment and lightly butter it.
Then mix the milk, butter and a bit of salt together and bring to a boil, then remove from the heat.
Then mix the sugar, corn syrup and water together, stirring until the sugar dissolves, which if you are a bit impatient will feel like it is never going to happen because there is only 1/4 of a cup of water and a whole bunch of sugar. But have faith, it will dissolve eventually.
After awhile it will look like this, pretty sugar bubbles. Then you stop stirring it and only swirl gently so that it can turn a nice golden color.
When it looks like this, add the milk mixture, which will be quite dramatic and bubbly, and recommence stirring.
Stir and stir and stir until it reaches the correct temperature, and remember the temperature is key, you wouldn't want to over cook it or anything like that....
When it is exactly 248 degrees, pour the caramel into the prepared pan and sprinkle with sea salt and let sit until it sets, which in my case took about 15 minutes and then it was rock hard slab.
Once it is ready, either slice or smash, depending on whether or not you followed the recipe correctly.