This cocktail is a dealer's choice in terms of base spirit. I'd go with a gin like Dorothy Parker or Jensen's Old Tom for something a little stronger. And for a less boozy cocktail, I'd choose a fino or manzanilla sherry. Have fun with this one!
A professional bar would use crushed ice for this style of cocktail, but you can make some at home and have a bit of fun, too. Add a few ice cubes to a sturdy Ziploc bag. Cover the bag with a towel and using a mallet (or any large, heavy utensil like a rolling pin or heavy ladle) crush ice (also helps with post-work tension!).
1 handful fresh mixed berries (strawberries, raspberries, blueberries, blackberries, etc.)
½ ripe mango, peeled, pitted, and chopped into 1-inch cubes
3.5 ounces fortified wine or 2 ounces gin/spirit of your choice
Mint sprig for garnish (optional)
Muddle the fruit delicately in a heavy-bottomed pint glass, just enough to release their own juices. Add liquor to the glass and stir to combine. Fill pint glass with the ice, top with Berry LaCroix, and garnish with a sprig of mint, if using.