Use the weight when possible, the cup measurements are not that accurate
1 tablespoons unsalted butter, melted, for buttering 12 madeleine molds
1/2 cup (70g) finely ground almonds
3/4 cups (95g) confectioners sugar
1/4 cup (35g) unbleached all-purpose flour
1/3 cup (92g) egg whites (2 to 3)
1/3 cup (3 ounces; 92g) unsalted butter, melted and cooled
Preheat the oven to 250F.
Spread out the ground almonds on a baking sheet and put in the oven for 7-8 minutes. Take out and stir it up and re-spread it every few minutes. The almonds should darken slightly and smell nutty. Take them out and leave to cool.
Preheat the oven to 400F.
With a pastry brush, use the 1 tablespoon melted butter to thoroughly butter the madeleine molds or muffin tins. Put the mold on a baking sheet and put the whole thing in the freezer to resolidify the butter and make the friands easier to unmold. Do this step even for non-stick pans, otherwise they will stick.
In a large bowl, combine the toasted almonds, sugar, and flour. Mix to blend. Add the egg whites and mix until thoroughly blended. Add the melted 92g butter and mix until thoroughly blended. The mixture will be fairly thin and pourable.
Spoon the batter into the molds, filling them almost to the rim. Place the baking sheet in the center of the oven.
Note: The timing and temperatures here need further experimentation:
Bake until the friands just begin to rise, about 6 minutes. Reduce the heat to 350F. Bake until the financiers are a light, delicate brown and begin to firm up, about another 4 minutes. If the tops are really light at this point, turn on the broiler for a couple of minutes to get some color on top.
Remove the baking sheet from the oven and let the financiers cool in the molds for 10 minutes. Unmold.The friands may be stored in an airtight container for several days.