1. Prepare the caramel mold : line an about 15cm x 15cm square caramel mold with parchment paper. Set aside.
2. In a medium non-sticky saucepan, combine milk, sugar, honey and vanilla. Bring it to a boil to melt the sugar. Shake the pan gently to redistribute the melting sugar over medium heat, but do not stir sugar at this point.
3. When the sugar dissolves, add heavy cream and butter. Whisk gently over medium-low heat.
4. Stir the mixture constantly, scraping the sides occasionally until it reaches a firm as shown in the pictures.
5. The mixture will get bubbly and thick (see pictures). The process will take about 40 to 60 mins (Depend on the heat level).
6. Stirring the caramel will become harder. If you like soft caramels, then stir less. You will get a better feel for the perfect timing after several trials :-)
7. Pour the caramel mixture into the prepared mold. Sprinkle with sea salt if you like.
8. When the caramel cools to room temperature, refrigerate until cooled and hardened. If you have made harder caramel, I recommend you cut it before refrigerating as otherwise it will very difficult to cut.
9. Cut caramel into small pieces as you like them and, if desired, wrap them up in wax paper.