Preheat the oven to 350F. Line two baking sheets with parchment paper.
Cut the butter into cubes and place in a pan over medium heat. Stir as the butter melts, then continue to stir as the butter begins to bubble. After 3-4 minutes, the butter will start to foam up. Once the foam subsides, you'll see brown flecks of butter at the bottom of the pan. Turn off the heat and pour the butter in a bowl. Let the butter cool for 10 minutes, until it's no longer hot to the touch.
Place the browned butter, brown sugar, and granulated sugar in a large bowl. Use a stand mixer or hand mixer to mix until well combined, about 2 minutes.
Add the egg and vanilla extract. Mix until well combined, about 1 minute.
Add the flour, salt, and baking soda. Mix on low just until no streaks of flour remain. Add the chocolate chunks and mix on low until just combined.
Gently break 4-5 raspberries into smaller pieces, trying not to burst any juice.
Use a large (1/4 cup) cookie scoop to scoop out the dough. Place 1/2 of a raspberry on top of each dough ball, as well as an extra chocolate chunk. Place up to 4 dough balls on each baking sheet.
Bake for 8-10 minutes, until the edges are just starting to set. Top each cookie with a pinch of flaky salt. Let the cookies cool for 15 minutes on the baking sheet, then transfer to a cooling rack to cool completely. Enjoy!