For the Brown Butter
Cut the butter into 8 pieces and place it in a 2 or 3-quart saucepan. Place the pan over medium heat and melt the butter. As the butter melts, the milk solids will rise to the top and the butter will occasional bubble and pop. If it is popping a lot to the extent that butter splatters onto the stove top, reduce the heat to medium-low.
Continue to cook the butter, stirring occasionally until the milk solids drop to the bottom of the pan. The butter will turn golden brown and the milk solids will turn brown. Stir the butter, scrapping the bottom so the milk solids (brown particles) don’t stick to the bottom of the pan.
Once the milk solids have turned golden brown, pour the browned butter into a wide bowl and allow it to cool until it is just barely warm.
For the Blackberry Financiers
Once the butter has cooled, preheat the oven to 375°F. Melt one tablespoon of butter and brush the wells of a non-stick mini muffin pan.
Separate the eggs and place the egg whites in a medium sized bowl.
Place the sugar in a large mixing bowl. Zest one or two limes onto the sugar until there is about 2 teaspoons of lime zest. Use your fingers to rub the zest into the sugar, until the sugar turns a light green color.
Add the almond flour, all-purpose flour, and salt to the sugar and whisk for about 30 seconds until the ingredients are well combined.
Whisk the egg whites until they’re foamy. Add them to the dry ingredients and use a spatula to mix the egg whites into the dry ingredients. Scrape the bottom repeatedly to ensure all the dry ingredients are mixed in.
Add the brown butter and mix the butter into the batter until all the ingredients are well combined.
Divide the batter evenly between the muffin wells. Place a whole blackberry on top of each financier. Bake the financiers for 12-14 minutes, until the cakes have risen slightly and the edges are golden brown.
Remove the pan from the oven and allow the cakes to cool in the muffin cups for 10 minutes. Use an offset spatula to remove the cakes from the muffin cups. Place them on a cooling rack and allow them to cool completely. Enjoy!
The financiers can be stored in an airtight container for up to 3 days. If in a warm or humid climate the financiers can be stored at room temperature for 1 day, then refrigerated for 5 days. They can be frozen for up to 1 month.
This recipe works best with a nonstick pan, it will be easier to remove the financier cakes from the muffin wells.
If you have a 12-cup mini muffin pan instead of 24, you can make the financiers in two batches. After filling the pan for the first batch, store the batter in the refrigerator. Bake the financier cakes following the directions above. Remove the cakes from the pan, wipe out the wells with a paper towel and allow the pan to completely cool. Brush the pan with butter and add the batter for the second batch.