Spray an 8×8 pan with non-stick spray.
Add semi-sweet chocolate to a double boiler, and melt completely. One melted, remove from heat and slowly add in sweetened condensed milk and vanilla extract, stirring with a large spatula until mixed. The chocolate will be thick. Begin in stir in bourbon 1 tablespoon at a time – mixture is going to get super thick but slowly stir and just fold the chocolate mixture over until combined. Use the spatula or a large spoon to spread the chocolate in the pan. It will be thick! Don’t worry about the top looking pretty because we are going to cover it up. Just spread it evenly. Place in the fridge for 10 minutes to set.
Melt the milk chocolate and remove the pan from the fridge. Take a few small spoonfuls of the milk chocolate and using the back of a spoon, spread it evenly over the top of the fudge. Immediately cover it with the chopped caramel-filled candies, chocolate chips and chocolate toffee pieces. Take remaining milk chocolate and drizzle it over the top to set some of the loose candy. You can also use any additional sweetened condensed milk that may be left in the bottom of the can and drizzle it over top. Let set in the fridge for 30 minutes or so.
When ready to cut, fill a large cup with hot water. Dip a sharp knife into the water, then blot on a towel. Use knife to cut fudge into your desired size of squares.
Note: the melting can also be done in the microwave. I suggest melting the chocolate first on medium power in 30 second increments, stirring after each time. Once melted, add in remaining ingredients and stir until smooth.