Preheat oven to 350ºF. Line with parchment and lightly grease an 8x8” baking pan.
In a medium bowl, whisk the flour, salt, and cocoa powder together. In a separate bowl, rub the mint leaves into the sugar with your fingers for about 30 seconds, it should be very fragrant.
Put the chocolate and butter in a large glass bowl and microwave for 30 seconds. Stir, and repeat until the chocolate and butter are completely melted and smooth. Add the sugars. Whisk until completely combined. The mixture should be room temperature.
Add 2 eggs to the chocolate mixture and whisk until combined. Add the vanilla and stir. Do not overbeat the batter at this stage or your brownies will be cakey.
Sprinkle the flour mixture over the chocolate mixture. Using a rubber spatula (not a whisk), fold the flour mixture into the chocolate until just a bit of the flour mixture is visible. Fold in the chocolate chips and raspberries.
Bake in preheated oven for 40-50 minutes or until a toothpick comes out with moist crumbs attached.
Cool brownies completely before cutting into 16 equal squares with a very sharp knife.
Brownies will keep in an airtight container at room temperature or in the refrigerator for up to 1 week, or in the freezer for up to 3 months.