Place loaf pan (9.5 x 5.5) and a large glass or metal bowl in the freezer to chill (about 15 minutes).
In a small sauce pan, on low heat, combine milk and sugar just until sugar is dissolved (about 30-60 seconds). Mixture will be luke warm. Whisk in cocoa powder until well combined. Chill in freezer for 20 minutes or until cold.
(Do this once the cocoa mixture in the previous step has already chilled) Remove bowl from freezer. Pour heavy cream into the bowl and mix on high speed with hand mixer for approximately 4 minutes or until cream has the consistency of whipped cream.
Remove milk mixture from freezer and add into whipped cream. Stir until well blended and mixture resembles melted ice cream.
Remove loaf pan from the freezer and pour ice cream in to fill. Spread top evenly and place back into the freezer for 2-3 hours.
After 2-3 hours remove ice cream from freezer. Mix in most of pretzels and caramel, reserving some for the top. Once mixed, top with remaining pretzels and drizzle with caramel.