1. In a large microwave safe mixing bowl, add butter, and chocolate.
2. Pop it in microwave for 1 minute over medium heat. Remove from the oven, and stir it well. Repeat the process until chocolate melts.
3. Drop brown sugar in a bowl, and whisk it well. Let it stand for a couple of minutes.
4. Add eggs, one at a time, and beat after each addition.
5. Put sifted flour, cocoa, and baking powder in the bowl. Mix to incorporate.
6. Cut caramello nibbles into pieces, and throw it in the bowl. Fold to spread evenly.
7. Line mini muffin cups with liners, and spoon mixture in each one of them. Top them up with caramello nibbles.
8. Preheat oven to 180 degree C or 350 degree F.
9. Pop muffin cups in oven and bake for 20 minutes. Remove from oven and let it cool for 20 minutes.
10. Meanwhile for topping, in a microwave safe bowl, add dark chocolate, caramello nibbles, and thick cream.
11. Put bowl in microwave on medium high temperature for 30-45 seconds. Remove from oven and stir. Repeat until chocolate melts.
12. Top muffins with chocolate topping, and serve immediately.