Preheat the oven to 350° and line two large baking trays with parchment paper or a silicone baking mat.

In a medium sized mixing bowl, sift together the powdered sugar, cocoa powder, and salt. Add in the egg whites and vanilla and stir until it is all thoroughly combined, then mix in the dark chocolate chunks. It will be a bit like brownie batter, not runny but not a stiff dough either.

Portion the dough out into balls about 2 Tbsp. in size, then bake for 10-12 minutes. They are done when the tops look dry and shiny all the way across, with no darker sections in the middle.

Once the cookies are baked, allow them to cool for a few minutes, then remove them to a cooling rack and cool completely.

After the cookies have cooled, melt the white chocolate in a microwave safe bowl in 10-15 second increments, stirring between each to prevent the chocolate from burning. Once it has all completely melted, use a spoon to cover half of each of the cookies with it and place them back on a lined baking tray. Sprinkle with the crushed raspberries immediately, and place the baking sheets in the fridge until the chocolate has set.

Keep in an airtight container for 4-5 days.