Add butter to a small skillet and melt over medium heat. When butter has fully melted, continue to cook until it turns light brown and has a nutty smell, about 2-3 minutes.

Pour butter into a shallow bowl and cool for 15 minutes in the refrigerator.

Combine both sugars with the orange zest.

Add to the bowl of a stand mixer, along with the eggs.

Using the whip attachment, beat eggs with sugar for about 4 minutes on high speed, until mixture has thickened and has roughly doubled in size. Beat in the milk and vanilla.

With a sifter or fine-meshed sieve, add flour, almond flour, baking powder, and salt to the mixer bowl. If all of the almond flour won’t go through the sifter, just pour the rest of it in as is.

Fold the flour mixture in gently, adding in the melted butter before the flour is completely mixed in. Pouring in some of the browned solids at the bottom of the butter is fine, but leave anything overly browned in the bowl.

Spray madeleine pan with cooking spray and put in the freezer for 30 minutes. Put the batter in the refrigerator to chill during this time. Preheat the oven to 375 degrees Fahrenheit.

Remove pan from the freezer and fill each mold with a rounded tablespoon of batter—the amount should look like it would fill ¾ of each mold if spread out. Put the remaining batter back in the refrigerator.

Bake for 9 minutes, and remove when madeleines spring back if you touch them gently.

Bang tray on the counter gently when you remove it from the oven to loosen madeleines, then wait a minute or two and carefully remove the madeleines onto a cooling rack.

Let cool, and sprinkle with powdered sugar to serve.

Wipe out the pan, and chill again for 15 minutes, before filling with the remaining batter and baking.