optional: additional melted white chocolate for decorating/drizzling
Line a 9x9 inch pan with foil and lightly grease with cooking spray. Set aside.
Place butter in a large microwave-safe bowl. Cover with a paper towel and microwave on half power until completely melted. Add brown sugar, corn syrup and sweetened condensed milk and stir to combine.
Microwave on high for 4 minutes. Remove, stir, and return to microwave for 4 minutes. Remove, stir and return to microwave for 4 minutes. (You should be up to 12 minutes total now).
Microwave for 2 more minutes and stir, stir in vanilla and sea salt, then pour into prepared foil-lined pan. Allow to cool completely at room temperature OR for a quick trick, pop the pan in the fridge to speed up the cooling process. Once firm, proceed to the next step, about 3 hours.
Lift the foil from the pan and lay on a flat surface. Use a sharp knife to cut caramels into squares.
In a medium-sized microwave-safe bowl melt candy melts on half power for 2 minutes and stir until smooth. (Return to microwave at half power in 20-second increments if needed until completely smooth when stirred).
Place a square of caramel on a fork, then dip into the melted chocolate, use the fork to turn it over a few times to make sure it's completely coated, and then use the fork to lift (do not stab) the caramel from the chocolate. Tap the fork on the side of the bowl a few times to shake off any excess chocolate, then transfer to a sheet of wax/parchment/foil to cool completely. Repeat with remaining caramels. (To speed up the cooling, you can line a dinner plate with foil and place dipped caramels on the foil, then place in the freezer for 2-3 minutes)
Optional: use melted white chocolate to decorate cooled caramels. Store at room temperature in airtight container up to 5 days.