In a small saucepan, melt butter over medium heat; reduce heat to low, and keep warm. (Alternatively, in a small microwave-safe bowl, heat butter on high until melted just before using.)
In the bowl of a stand mixer fitted with the whisk attachment, beat eggs, sugar, orange zest, and salt at high speed until pale, thick, and nearly tripled in volume, about 4 minutes. Whisk in buttermilk, orange blossom water, and vanilla bean paste.
In a small bowl, whisk together flour and baking powder. Using a balloon whisk, gently fold flour mixture into egg mixture just until combined. Add very warm melted butter in two to three additions, gently folding with whisk after each addition until well combined and smooth. Cover with plastic wrap, pressing wrap directly onto surface of batter, and refrigerate for at least 2 hours, preferably overnight. (Batter can be refrigerated for up to 2 days.)
Preheat oven to 375°F (190°C). Spray a 16-well nonstick madeleine pan* with baking spray with flour.
Transfer cold batter to a pastry bag, and cut a ½-inch opening in tip. Divide batter among prepared wells (about 25 grams each).
Bake until golden brown with a domed center (edges will be deep golden brown) and an instant-read thermometer inserted in center registers 200°F (93°C) to 210°F (99°C), about 8 minutes. Let cool in pan for 3 minutes. Remove from pan, and place on an ovenproof wire rack over a parchment paper-lined baking sheet. Reduce oven temperature to 170°F (75°C).
Dip both sides of warm madeleines into warm Crisp Citrus Glaze to coat with a thin layer. Let stand, bump side up, on prepared rack until set, 2 to 3 minutes. (If glaze begins to set, gently reheat over steaming water as needed.) Dip again for a second coat of glaze. Place in warm oven with door cracked to crisp glaze, about 2 minutes. (Alternatively, let stand at room temperature until dry, 10 to 15 minutes.)