Preheat your oven to 375°F (190°C). Grease and flour madeleine molds or use non-stick madeleine pans.

In a mixing bowl, whisk together the eggs and granulated sugar until the mixture becomes pale and slightly thickened.

Sift the flour, ground pistachios, baking powder, and salt into the egg mixture. Gently fold the dry ingredients into the wet ingredients until just combined.

Add the melted and cooled butter to the batter, along with the orange blossom water and orange zest. Stir until all ingredients are well incorporated and the batter is smooth.

Cover the bowl with plastic wrap and refrigerate the batter for at least 30 minutes. Chilling the batter helps the madeleines achieve their characteristic hump when baked.

After the batter has chilled, spoon it into the prepared madeleine molds, filling each mold about 2/3 full.

Bake in the preheated oven for 10-12 minutes or until the madeleines are lightly golden around the edges and spring back when gently touched.

Remove the madeleines from the molds and let them cool on a wire rack.

Once cooled, you can dust the madeleines with powdered sugar for an extra touch of sweetness if desired.