Take full-fat ice cream and gelato and melt enough that you want to work with - not totally - just enough so that it is easy to mix.
For chocolate-brownie-fudge, add in cut up brownies and melted ganache.
Pour these ingredients into a container and add more toppings.
Freeze overnight - at least 12 hours, and scoop to your heart's content. Because the base is real ice cream, it will re-freeze properly and scoop nicely, as if it never melted in the first place.
Now you have upgraded premium ice cream scooped at home, with all the yummy chunks and flavor you want, frozen into the ice cream, just like you would enjoy if you were at an exclusive ice cream shop.
Here's an example of Blueberry Cobbler Ice Cream.