Cover a baking sheet and your work surface with parchment paper. Set aside.
Wash apples well to remove waxy coating. Dry, then insert a stick in the stem end of each apple.
Break chocolate into pieces and place in a small bowl. Microwave at 30 second intervals, mixing well in between, until melted.
Transfer melted chocolate to a zip top bag, then seal. (A pastry bag or plastic bottle with a pointed nozzle works, too.) Set aside.
Unwrap the caramels and place them in a small bowl. Add heavy cream and a generous pinch of salt, if desired, to the caramels.
Microwave caramels for one minute, stir, then microwave for another minute. Stir caramels again, then microwave for 30 more seconds or until caramel is hot and smooth (it should drizzle thinly off a spoon).
Grab an apple, blot off any condensation with a paper towel, then dip the apple in caramel. Use a spoon to pour caramel over the apple, if needed.
Allow excess caramel to drain off apple, tapping it gently on the bowl's side.
Transfer apple to the parchment lined baking pan, then repeat this process with the remaining apples. Work quickly and reheat the caramel, if needed.
When the apples are coated, pick up the first one you worked on. If there is caramel pooling on the bottom, press it toward the bottom of the apple.
Snip a small corner off the chocolate-filled bag, then drizzle chocolate back and forth over the apple, rotating the apple to coat all sides. Avoid the bottom ¼ of the apple.
Press M&M'S® Caramel, one by one, into caramel on the bottom ¼ of the apple. If the candy won't to stick, dip it into a bit of the hot caramel, then try again.
Return apple to the baking sheet, then repeat this process with the remaining apples.
Allow chocolate and caramel to cool and set for a few minutes before eating. Enjoy!