In the glass you are serving in or in a cocktail shaker, muddle together the sugar you are using with the fresh mint, minus a few sprigs for garnish. Really get in there and bruise up the leaves to release their oils.
Top the muddled sugar and mint with the cold brew and cream. Put the lid on the shaker and shake shake shake. Alternatively you can just give it all a good stir in a glass, but I like the frothiness from shaking.
Pour over ice, straining the muddled mint as you pour, garnish with the remaining fresh mint sprigs and serve.
Notes
If you prefer you can make a simple syrup that is 1 part sugar to 1 part water and infuse with about 1/2 cup chopped fresh mint. And use this in place of the fresh mint and muddling. You can use hot coffee or espresso and ice it down, as well. Play with the ratio and add more of less cream and sweetener, you can easily make it to your liking.