Preheat the oven to 350°F (175°C). Line the cups of a mini muffin pan with paper cups and set aside.

Heat the butter in a small stainless steel pot over medium heat until completely melted and simmering. Keep on cooking over low heat, swirling the pot from time to time. If the butter bubbles up preventing you from watching closely over the color changing (that’s the water evaporating), lift the pot off the heat for a few seconds until the bubbles recede, then put back on the heat. The butter is ready when the milk solids at the bottom of the pot turn a light brown color and the concoction gives off a delicious hazelnut aroma. When it does, remove the butter from the heat, pour in a small bowl, and let cool completely. (Congrats, you just made brown butter!)

Put the ground hazelnuts into a large mixing bowl. Add the flour, sugars, and baking powder, and whisk together. Add the egg whites and whisk until they are fully incorporated and the mixture is thick and somewhat sticky. Whisk in the brown butter. At this point, the dough can be stored in an airtight container in the fridge for up to 2 days.

When ready to bake the financiers, drop a tablespoonful of dough in each prepared muffin cup. Push a fresh cranberry in the center of each financier. Bake for about 12 minutes, rotating the pan halfway through, until the financiers are golden brown on the edges. Let cool for 10 minutes in the pan and then transfer to a cooling rack to cool completely.

Financiers are at their very best when freshly baked, but you can also store them in an airtight container at room temperature for up to 3 days.