Pre-heat oven to 375F, with a rack in the middle position.
In the bowl of a stand mixer fitted with a whisk attachment, add the egg whites. Or, you may also use a hand mixer or large balloon whisk (plus some elbow grease!) and a medium-large bowl that is more deep rather than wide to help the folding process later on.
In a separate medium bowl, whisk together the sugar, almond meal, all purpose flour and sea salt. Set aside.
Whip the egg whites on medium-high for 1-2 minutes, until fluffy (speed 6, 2 minutes on my Kitchen Aid) OR you may do this by hand or with a hand-style mixer. The goal is medium-soft peaks that hold their shape but are not dry and brittle (over-beaten).
Immediately sprinkle ⅓ of the dry mixture over the beaten egg whites, and gently fold in with a large spatula. Continue until you’ve added the remaining dry mixture.
Add the slightly cooled browned butter, and fold in until the mixture is combined - do not over-mix.
Using a spoon or cookie scoop, divide the batter in the muffin tins. The tins will be about 2/3 of the way full, depending on how much air your batter has retained after folding. The cakes are meant to be small - so you may get more out of your batter than 12.
Top each with the berries, using only a few per financier - using too many will result in too much juices oozing out and a soggy financier.
Bake for about 20 minutes, until the tops are golden brown. Test with a knife or toothpick - plunging into the center of one - checking to make sure it comes out clean.
Remove from the oven, and allow to cool in the tins for 10 minutes. Using a small off-set spatula or thin butter knife, remove the financiers and place on a cooling rack to finish cooling.
Enjoy plain, with a sprinkle of confectioners sugar, or however you’d like! Best the day they are made, but still very edible a few days after. Store in an air-tight container at room temp or in the fridge.