How to Make It
Preheat the oven to 350°F and line a 6-cup muffin pan.
Place the butter in a small saucepan over medium heat and cook until the aroma is nutty and the milk solids start to turn brown on the bottom of the pan, about 5 minutes. With a spatula, transfer the browned butter into a large mixing bowl. Add the brown and white sugars, eggs and vanilla to the bowl and mix until combined.
Whisk together the flour, ground hazelnuts, baking powder and salt. Pour the dry ingredients into the browned butter mixture and mix until fully incorporated. Gently fold in the raspberries.
Spoon the muffin batter into the paper cups. Scatter the tops with a few of the cracked hazelnuts, while gently pressing them securely into place. Bake for 15-18 minutes, until a cake tester inserted in the center comes out clean. Let the muffins cool briefly in the pan, and then place them on a wire rack to cool.