• In small bowl, sift almond flour and powdered sugar; set aside.
• Beat egg whites and half the granulated sugar to soft peak. Add remaining sugar, salt, vanilla bean powder and flavoring; whisk to stiff peaks.
• Add almond flour mixture to meringue; gently fold until the mixture is smooth, shiny and slightly runny.
• Pour the mixture into a piping bag and pipe out ¾-inch mounds on either parchment paper or a silicone mat. Tap the pan a few times to remove air bubbles. Let them rest for 30 minutes or until they appear dry on top.
• Heat oven to 400F. Turn oven down to 300F and place macarons in oven. Bake 15 to 20 minutes or until puffed and appear dry but not brown.
• Let cool on pan for 15 minutes before transferring to cooling rack.
• Pipe or spoon cooled citrus curd on flat side of half the shells. Gently place second shell on top.

For Vanilla Citrus Curd

• Whisk egg yolks, sugar, zest, vanilla bean powder and salt in a heat-proof bowl or double boiler. Place bowl over simmering water (do not let bottom of bowl touch the water) and continue whisking until thick like pudding. This will take 5 to 10 minutes. Remove from heat and whisk in the butter. Cover surface of curd with plastic wrap; chill.